Before solvers people still implemented strategies, so I'm not sure what you mean when you ask what my exploitation is based on.

I think GTO is a great way to think about the game. I don't think studying solvers is important to understand the game well, or GTO. When solvers provide an insight, it generally trickles out to the poker community and we all hear about it. It's much easier to digest traditional educational content than to futz around with a solver, and a much better use of time for a new player.