As long as a person takes care of their credit, having limits that meets yearly income or even exceeds yearly income could gain that person not only high scores but also creditors offering products with excellent terms attached.
Again, as long as a person is taking care of their cards by keeping utilization down, paying on time (preferable in full), never going overlimit, etc. (which is what you say you are doing)

The “only” time you should really carry a balance and make payments on a credit/charge card is when you have a 0% interest promo for x number of months.

Since you state that you have no problem controlling your spending and you pay in full every month, you are proving to all creditors (current and future) that you are a good risk.

I wouldn’t recommend cancelling the cards that the promo’s have expired.
You might keep the cards locked up and pull them out every once in a while, make a small purchase then pay when you get the statement. Allow them to continue to raise your scores.

It sounds like you should have a decent credit history, by what you have posted. So closing the occasional card should not have a major impact on your scores

But opening cards for the promos, then closing them after the promo’s expire will show an unstable credit history and will eventually send red flags to any future creditors. You will probably find it harder and harder to be approved even if your scores are high.

So, yes, having too many credit cards or too much credit available makes you look like a high risk. This can lower your credit score and make banks think twice before giving you a loan.

Canceling cards wont generally affect your credit score.