There's a tendency in life for people to look at the past with rose-tinted glasses. While I get it to some degree, it's always struck me as a little odd. I have fond memories of the past, but I very rarely want to go back; even when times are hard in the present, I'd still rather be the person I am today than the person I was back then, and I imagine my future self will feel similarly about my present self. Life is a series of stepping stones, and I'd rather progress forward than backtrack.
Regarding cons, my experience with them today is radically different than it was when I attended my first Otakon in 2008, and not just because I went from being an attendee to a vendor. Cons have become wildly more inclusive and safer spaces for all walks of nerddom. Bad behavior is called out more often, and organizations like the Cosplayer Survivor Support Network exist to help cons establish and strengthen their harassment policies.
Are things perfect? No, but we can recognize the progress that has been made, and it can motivate us to keep seeking perfection. I look forward to seeing what cons become in the future.
Rock on, guys, and never stop drawing.