For mass adoption to take place, regulation of this technology is the only way. Many people are still in doubt of this technology simply because of the risk involved. It would be a downward process; Countries to big organizations to small investors and to normal people. In order for normal people to trust this technology, it should be first acknowledged by big industries first. And I doubt it is services Bitcoin is needing for such thing to occur. Bitcoin is simply a digital currency and will only be used as an alternative mode of payment to fiat. It just happened that volatility exist which generates profit for those who manage to make use of the changes on their market price from time to time.
Well, I personally think that there are a few key services that need to be developed further in order to make Bitcoin more usable for the masses.
First off, we need more Bitcoin decentralized exchanges or DEXs. While DEXs are popular in the Ethereum ecosystem, Bitcoin DEXs are still low volume and illiquid, which leads to terrible prices.
If we can start seeing Bitcoin DEXs with much higher volume and prices closer to market price, then it will become much easier for people to buy Bitcoin privately without getting tracked by centralized exchanges.
Secondly, we need a Bitcoin-first popular website that can become the "Amazon for Bitcoin". While it's great that more and more e-commerce websites are starting to accept Bitcoin as a form of payment, we still need a major player in the online shopping space that operates exclusively in Bitcoin. That way, people can easily buy things online with Bitcoin without having to worry about converting it to fiat first.
Lastly, I think we need a decentralized collateralized lending platform that's specifically designed for Bitcoin. Non-collaterized lending with Bitcoin just won't work due to legal enforcement issues, but collateralized lending can work because it already involves financial enforcement.
This would give people with a lot of their wealth tied up in Bitcoin the option to leverage that wealth without having to risk it on a company that might fail.