It's not just possible, it's already happening, and happening very fast! Be ready!
It is possible if we scale via off chain solutions. If we focus on scaling via the main chain we will end up centralizing (further) both miners and nodes. The question is where is the limit (e.g. what node count should be considered centralized)? This visualization could be expanded with the Lightning Network added to it (although not sure when we should expect a release).