I don't know you man, I don't know what you're life is about, but I hope you have people in you life you can seriously talk to about feelings like that.

Your hobbies don't define you, there's no such thing as wasted time. Shit your entire collection could have been peer pressure or competitive in nature, and you just lost your fizz when you primary foil moved on. That doesn't mean the time you spent is worth any less, or didn't contribute to your life in some meaningful way.

Is it normal to have a midlife crisis at 30ish, fucking absolutely! You'll have many crisises, you've probably already had crisis in the past, you'll continue to have crisis in the future. You would be a terribly uninteresting person if you didn't.

If selling some or all of your collection would make a positive difference in your life, and you're questioning why you even have them, then yeah, sell some. You probably won't regret it, those items will continue to have a life and be valued by someone else. But if the thought of selling hurts too much, then it's not time yet. That's ok too.

Just give yourself a break!