It also suits merchants, because it offers them a way to operate with less fees, than what is offered by PayPal of Visa (assuming the network is fine, and the scalability problem is solved).
But the problem is still not solved, and therefore it does not suit merchants
I agree with you, but there are possible solutions that will be implemented in the future. The lightning network is not just in paper, it's already being tested both in BTC and LTC, on a testnet. We already saw an atomic swap with the LN between LTC and BTC. Also don't forget that segwit, although it's already implemented, it's still not being used by all wallets and exchanges. This will help with fees, so I guess that if people are not using it right now, is because they are not that worried with the actual fees.
it does not require the interference of a middle man (banks).
The new middle man is the miner. You will be forced to accept their high fees like we saw recently, or your transaction will take days or not go through at all
Again people are not really worried about this apparently, because most of them are not already using segwit, and they could. The LN will again solve this, and is already being tested. Finally if you compare the fees to what you get for international transfers, or even using third party services like Neteller or PayPal or even Visa, you will see that they are not that high (depending on how fast you want your money through). There is a reason why you see some schools and universities already accepting BTC as a payment, and declining Visa.
Bitcoin can fail, but not because it's bad or useless. Bitcoin can fail because people are greedy.
Well, if there is one thing we know for sure in 1000 years of human history it is one thing: People are greedy.
Therefore by your own argument, Bitcoin will fail
Yes you are correct about this, but this is not a BTC problem, and everything else is affected by this as well. That's one of the reasons we keep having economic crashes. The thing is, there is not much we can do about that, because we depend on services that are offered by greedy people, even if we are not greedy ourselves. This is actually one of the reasons BTC was created in the first place, so that we have a chance to try to depend on our own choices.