The funny thing is most people are still leaving their coins on a centralized exchange
Not anymore as before, seing the present experience they are having with the government regulations and how fear has gripped the heart of many users of centralized exchanges, if you're current with the recently news, you will discover a drop on the rate of investors using centralized exchange, also the highest numbers of the whales are having their bitcoin on non custodial wallet.
hoping people to run full node is completely impossible.
It's possible, everyone may actually not get used to that but many would have preferred that while some will choose the use of other means of using a cold storage for their bitcoin, but the interesting oart of this information is that some will see this and take action right away.
The reason is they don't want to pay extra fees, downloading a lot data, waiting their wallet to sync, they not only hold Bitcoin etc.
I think paying the fee and other requirements needed in running a full node is not the real issue they can have problem with, but the technicality in doing so may be very challenging to users to run a full node.
Changing people view as become your own bank is really hard task because people still rely with centralization and only use Bitcoin due to making profit.
Not everyone but this can be applied to everyone, some use it as a store of value, assets and even preferred currency to using, I've heard of the story of a man who only make use of bitcoin for making payments daily, that was his own choice, this has been discussed some times ago here on the forum.