Hi @crypto.piotr,
SBC stands for Steem Blockchain, it's just an acronym I made up :) I think people can adapt to a decentralized system. We all did. Also things can get a lot easier than they are now. It's more from a lack of money/time/experience that this is all so hard now. It might not ever be as easy as Facebook or Instagram, but it can definitely get a lot easier than this.

The SPS will fund things that are good investments. I don't think account size matters, but there is an element of trust, so people might tend to trust someone with more stake in the system more. I also wouldn't throw a bunch of money at someone I don't know, that wouldn't be very smart.

Thanks for reading :)