My favorite genre doesn't exist anymore

I saw someone on a different music sub saying that it's impossible to be a true fan of a band if they are inactive. That you'll never experience what was like when they were together, therefore making you a fake fan.

My favorite genre is grunge (I've heard a million times that it's a scene not a genre but idk). It doesn't exist anymore. 3/4 of the big 4s front men are dead. Although AIC is stilling going with a new one who I love.

The person on the other sub said to find artists that are still going (especially new ones ) and it's just been making feel bad for liking old music. I like a few new artists (Tyler the Creator, Olivia Rodrigo, Phoneboy, Bring Me the Horizon to name a few) but I mainly like Alice in Chains, Mad Season, Hole, Nirvana, Pearl Jam, Soundgarden, the Vaselines, the Wipers to name a few others.

Is this a failure as a music fan for mainly liking older bands? I feel the need to mention that I am autistic and finding new things is very hard for me. It took about 10 listens for me to get into Sempiternal by Bring Me the Horizon for example.