People don't use Bitcoin because it's complicated and unstable. It's complicated and unstable because the types of people that use it want to speculate with it or use it for illegal purposes. Just making it more approachable won't fix the stability issues, so it likely won't increase the number of users in a meaningful enough way to get it to take off.
The same is true for desktop Linux. And installing Linux is often easier than installing another OS (Windows or macOS). Take Ubuntu or Mint, for example. They're the most popular among users new to Linux, and installation is as easy or easier than Windows since drivers come preinstalled and the user is prompted if proprietary drivers are available. The problems arise when trying to use software not deigned for Linux (e.g. MS Office), and this is getting better all the time with investment into the Windows compatibility layer by Valve.
However, the chicken and egg problem will always be there. A decentralized system like Bitcoin can't really be saved by investment from a third party since it can't solve the volatility problem without centralization.
For this reason, I think looking at centralized, but not government run, systems is interesting. For example, GNU Taler is a centralized cryptocurrency that can be used for anything (one example was currency used at conferences) with incredibly low transaction costs. I think it's interesting because it gets people used to using something digital (and not government provided/managed) to make transactions, but without having to deal with volatility inherent in cryptocurrencies, and once cryptocurrencies stabilize, perhaps they can be a drop-in replacement.
I really want decentralized currencies to work out (largely to make traveling less of a pain), but nothing I've seen is worth making more user-friendly.