If you're willing to restrict the flexibility of your approach, you can almost always do something better

It's nice to have a game that sells a million copies.

The situation is so much better for programmers today - a cheap used PC, a linux CD, and an internet account, and you have all the tools necessary to work your way to any level of programming skill you want to shoot for.

It is not that uncommon for the cost of an abstraction to outweigh the benefit it delivers. Kill one today!

I like to think I'm pretty good at what I do.

Focused, hard work is the real key to success. Keep your eyes on the goal, and just keep taking the next step towards completing it. If you aren't sure which way to do something, do it both ways and see which works better.

It is difficult to make good scalable use of a CPU like you can of a graphics card. You certainly don't want 'better or worse' physics or AI in your game