The piracy scene (with 0-day FTP etc.) worked fine before BT was even well-known.
And there are more than enough groups directly release their content on public trackers for anything remotely popular (any Netflix series fall into this category). You (or they) don't need PT for that.
PT is kinda essential if you're interested in obscure/niche content though, I agree.
I hate private trackers purely due to (my personal) value. I think it's a violation of "piracy spirit", and it somehow enables lots of people/groups' superiority complex or unnecessary gatekeeping behaviors (emphasis on "unnecessary": I know by definition it's not gateless).
But I do acknowledge it's probably the most practical way nowadays.