I just saw this topic "What problems in Bitcoin's infrastructure prevent it from being adopted more easily?". All the answers were really interesting, mentioning the lack of regulation, volatility, ignorance, etc.
In my opinion, regulation, practicality, and stability are definitely required for the mass adoption of crypto as a payment method/currency.
Lets start by clarifying that there is a big difference between "crypto" as in altcoins and "bitcoin".
To get any adoption, let alone mass adoption for altcoins you first have to produce a useful altcoin which we still don't have. The only utility altcoins provide so far is pump and dumps.
As for bitcoin the only reason that has slowed down adoption is the fact that bitcoin is a new technology that people aren't familiar with and like any revolutionary technology it takes time to be adoption. The internet or any other similar new technology didn't reach mass adoption overnight, so you shouldn't expect it to happen to bitcoin fast either.
On top of that there is a lot of misinformation about bitcoin misleading and discouraging people every day. That too slows down adoption.
Things such as lack of regulation, volatility, etc. are silly irrelevant reasons. Bitcoin as a decentralized currency doesn't even need regulation! and volatility is because of lack of mass adoption.