Let's get this out of the way, nerds need to stop talking about whether or not Sonic is cool anymore. Not only do most of us not keep up with what's cool in the outside world, but many nerds think cool only equals to just what they think is so when it's not. I could say Micky Mouse is cool, that doesn't make him so, and I'd just be calling him that. It's a matter or using a definitive word with something that isn't definitive with it. Let's look at the definitions.
of or at a fairly low temperature:
"it'll be a cool afternoon" · [more]
synonyms: chilly · chill · cold · bracing · brisk · crisp · fresh · refreshing · [more]
fashionably attractive or impressive:
"I always wore sunglasses to look cool"
synonyms: fashionable · stylish · chic · up-to-the-minute · sophisticated · trendy · [more]
(a cool ——)
used to emphasize a specified quantity or amount, especially of money:
"a cool $15,000 to buy the franchise"
a fairly low temperature:
"the cool of the night air"
synonyms: chill · chilliness · coldness · coolness
"he recovered his cool and then started laughing at us"
synonyms: self-control · control · composure · self-possession · self-command · [more]
the quality of being fashionably attractive or impressive:
"all the cool of high fashion"
You can see that aside from temperature, Cool is defined by style and composure, not ones personal opinion, not in the case when we argue with Sonic anyway, and the definitions of cool are what made Sonic cool back in the day, and they never stopped being cool. Since Sonic fits the definition of cool, how can he stop being cool? Only when Sega themselves changed him to fit the views of fanboys, and in reality, Japan and the US have totally different cultures so cool would be subjective between us, but the word itself isn't. Though, this goes into a bigger problem with too many people attributing everything to subjectivity and not wanting to face the objectivity, usually out of their own bias or in most cases, even my own sometimes, being an outsider. Nevertheless though, what made Sonic cool never stopped being cool to all but a group of people within our culture. Even those on different sides of the spectrum who don't think Sonic is cool are opposed on the word. You have those who mainly play mature games, but conform to more things that fit the definition of either cool or the subject of mature for video games. The other spectrum, the side that mainly stick with kiddy and colorful games, the side this fanbase is plagued with, shows a hatred for most cool things and rely only on their opinion. Look at how many people are triggered by the terms "dark and edgy" and look at exactly what kind of gamers they are. We do have some folks in this fanbase who are ambiguous on the spectrum, like certain youtubers who say Sonic is a cartoon animal and shouldn't be taken seriously, but turn around and indulge in mature games, not many I've seen though, but I'm pretty sure this is the case for Some call me johnny. Either way, his opinion on Sonic goes outside of what Sonic was crafted for and going by his own opinion, which is what I just described before.
On another note, of Cool really was a term that keeps changing, which it doesn't, then why have the Ninja Turtles remained relevant for 30 years? You can't say because they kept changing when many people consider the 2000 series to be the best of the franchise, me included. What gets the point across even more is that it's the best of the franchise because unlike the original 8's cartoon, the 2000 series was heavily based on the original comic that feature blood and Shredder being killed off in the first issue. The 2K series changed some of these aspects, sure, but it was much more faithful to what made them cool, not a false perception that they need to be cute and colorful because their cartoon animals. This is a way of thinking that only exists within the Sonic fandom, brought in by people from the outside or preconceived notions, as well as Japan, as they view characters like Sonic as just for kids when in the U.S., cartoony animals were popular with all ages, well into the 90's, as many adults at this point grew up with characters like Bugs Bunny and Hannah Barbara toons, which were far less childish then what we see with cartoons nowadays. I think that's what makes the key deference there, we grew up with cartoons that would play themselves straight while Japan, as far as I know, haven't, therefor the notion is more restricted over there. TMNT gave the idea that anthropomorphic characters could be more then comedians, and with that, the 90's saw many copies of them like the Mighty Ducks and Swat Kats, the ladder has many people waiting for a revival that's being worked on and excited for it. This means with almost 20 years of absence, what made Swat Kats cool still works for them now because they never stopped being cool. This also remind me of when youtuber Clement made a video, or videos, about how 06 was bad. I was never able to get past the first 10 minutes because of how idiotic he sounded about Sonic being serious, but one thing stuck with me since then. He made a big issue about how Sonic is a cartoon and cried this multiple times, his bitch ass voice during this bit still rings in my head to this day. "SONIC IS A CARTOON! SONIC IS A CARTOON!". This has always made me wonder what cartoons he was watching as a kid, because again, we had shit like Swat Kats and Mighty Ducks, and this dude is crying over 06 AND Shadow at the same time. Even with the toons I just called out, you know what was also a cartoon? Spawn - the animated series, Fritz the Cat, Heavy Metal, and Coonskin. Look them up on youtube if you're of age. If not, I can only hook you up with this TV Trope link.tvtropes.org/pmwiki/pmwiki.php…
So I'm left to wonder have Clement completely missed this entirely? You can't say he just means Sonic because he's judging Sonic based on him "being a cartoon".
Too many people in this fandom will never understand this, hence why they don't understand Sonic or the concept of cool, because they can't handle information that goes beyond their own opinion, which is something Sonic was meant to do, him being an anti-thesis of Mario. That right there shows again how much Nintendo fanboy is in these kinds of people.