Is there any rational explanation behind the fact that a Bitcoin forum -I repeat, a Bitcoin forum- is full of casino signatures?
It's quote simple: companies advertise to earn money.
is Bitcoin development so difficult? Is it a thing from the past? Nobody writes bitcoin-related software anymore?
Who's going to pay for those ads?
Is it because bitcoin projects can't be easily monetized?
Is it because even if they were monetized, they couldn't have the profit margins that casinos have, so they could be efficiently advertised?
That makes sense, right? A few dollars per post is a lot more money than any other forum would be able to pay.
Btw to be fair, I think that the biggest users of a signature campaign on this forum should be exchanges like Binance, Coinbase and Kraken.
They all have millions of customers, why would they use Bitcointalk? I'm pretty sure they don't even care about Bitcoin, especially the first one in your list who actively tries to trick their customers into withdrawing fake made-up tokens which they present as if it's Bitcoin.
Other large projects (I'm thinking about the #2 in market cap, a centrally controlled altcoin) only used Bitcointalk to promote in in their early days. The moment they got rich enough, they abandoned the forum just like they abandoned their "code is law" rule.