This hasn't been my impression. Especially amid Square, HoneyBadger, and PlebQR making it very easy to either accept bitcoin as a merchant, or for users to pay in bitcoin to another user who pays in fiat for the good being purchased, building in p2p exchange functionality and payment all in one step. I think the big companies jumping into Bitcoin pre-blocksize war were adopting a shiny new thing but not in a particularly sustainable way to begin with, and they were never prepared for the continued volatility. At the end of the day I don't want to spend Bitcoin at Amazon -- they can have the fiat. If I only have Bitcoin I can buy gift cards, but as someone who uses both in a spend and replace manner, the people I'm buying stuff from with Bitcoin are those who I legitimately want to support. If I resent that I'm buying from you in the first place but need what you're selling, you're getting the fiat. If anything really killed bitcoin payments though it wasn't blocksize considerations. It was the rise of stablecoins.