Centralized financial companies are constantly working on solutions to make transactions between different parties as easy as possible, however, the cryptocurrency and blockchain payment solutions are very complicated for the average person to use.
Until this is put in check, cryptocurrency payments will never have a chance to overcome fist.
No it isn't hard or complicated as you might think. I have read many whitepapers who aims to make blockchain and as such cryptocurrency achieve mass adoption; the problem is actually not cryptocurrencies, but rather the services they are built on (although a little percentage goes to the volatility of the crypto space). So to achieve mass adoption where cryptocurrencies will be used in everyday endeavours, the services they are built on need to be integrable with fiat payment systems.