So when is LISK going to launch for real, it already be delayed 3 times
May 24th is the first explicit launch date we gave yet. Our estimations were delayed, that's why they were estimations.
About the database switch -- SQLite sucks at concurrent writing (it locks the DB) and most probably this was the issue.
Yep. We knew of the concurrency problem all along, but the stress test really opened our eyes that SQLite is really much worse than we anticipated and needs to be switched out sooner than later. Regarding why Postgres, you should write Oliver a PM on our chat or here on BTT.