Yes, that's why multi-billion dollar professional sports organizations never, ever use them.
Regardless of whether you believe he was a mascot or honored symbol, can we all agree Chief Illiniwek did not perform the conventional duties of a mascot? To my knowledge, the Chief never fired a t-shirt cannon, posed for pictures with kids, dunked off a trampoline, or cut the ribbon at a grocery store opening.
I expect the pro-mascot folks would always have wanted a mascot, and in theory would have been clamoring for one before 2007. That thing in a crazy costume playing with the kids and trying to rev up the crowd during timeouts has
always been missing from Illini sports. Personally, I find mascots to be stupid and pointless, with few exceptions. But hey, to each his own. They are easy enough to ignore, and mascots are very far down the list of things that annoy me at sporting events.
College mascots are typically aligned with the team nickname. It seems much more common to have a pro mascot that doesn't have anything to do with the team name, e.g. the Suns' Gorilla or the Flyers' Gritty. Realistically, we're never going to have a conventional mascot that aligns with the name Fighting Illini. If the desire is to just have a mascot, I would humbly suggest those in favor should be proposing something totally unrelated to U of I or the state, i.e. something more like the Gorilla. There will always be people who are mad the Chief is gone, and anything that hints of a potential new team nickname is never going to get majority support.