I truly appreciate the response and I know I asked for a lot of education that I don't need. I'm a recreational rider and will never be more, I don't try to keep up with anyone so performance and speed are of little use to me. What I'm looking for is adaptability and durability mostly. When I say "as finances allow" I guess I really mean when the lower end stuff wears or craps out, can I replace it with better stuff so I get an improvement?

If I get a bike that comes with a sunrace triple crank because it's all I can afford, can it later be replaced with a higher quality Shimano or Sram triple crank without reengineering the whole bike?

Is there anything I should be looking for on a new bike that makes it upgradeable so I can throw a couple hundred bucks at parts every few years instead of buying a whole new bike every few years. That seems to be a better way to word it.