We don't need to worry about bitcoin futures, yes that's what Satoshi might have thought while programming the whole thing and made such that we can be sure about its bright future. The bitcoins concept is anyway unique and there won't be any advance technology as good as bitcoin is or what we can say blockchain!
There is very less chance that banking sectors will accept the bticoin though it has many advantages which they can use it in the domestic and international transaction. The reason is bitcoin's unregulated environment which may not be entertained by them and regulating it would be hardcore task for government. So the future is bright the way it is today.
Yes, he has designed the system in a way that bitcoins will keep getting more popular. With each day passing by, it becomes difficult to mine any more coins. This means that the supply will decrease and the demand is already on the rise. This will keep pushing the prices up benefiting all the investors. Another important thing to note here is that the developer is not involved with the system now directly. Once the whole system is set up, it is running on its won with the help of investors and bitcoin miners. I will say that future of bitcoins looks very promising.