Why do 90% of PH launches ghost their signups?

Genuine question for makers who've launched here.

I browse PH almost daily. I upvote stuff, sign up on launch day, leave comments. Then 3 days later I want to use a tool and can't remember the name.

I dig through upvotes, browser history, bookmarks - nothing.

And the thing is... not one of these products sent me a follow-up email. No welcome. No "here's how to get started." Nothing.

I get that nobody wants to spam, but there's a massive gap between spam and complete silence. Has anyone here actually nailed their post-launch email sequence? What worked?

Curious what the community thinks - is it laziness, fear of annoying users, or just not knowing what to send?