"What does BTCitcoin needed in order to become a mainstream payment system? "
To break barriers and make Bitcoin goes mainstream, you need to see it goes to big names in traditional markets and industries like big banks accept Bitcoin for their deposit, withdrawal, exchange with fiat currencies or CBDCs.
Big names can be big techs too but it is what we are gradually witnessing.
Sum up, wait for big banks to accept Bitcoin and mainstream Bitcoin will open that gate.
Another thing I'd like to note, like other things in life, thereare two sides, support and protest. There are people who never accept new thing from a day they know it till a day they die. Let them be.