I do the same thing as you. I buy tickets based on price and schedule without regard to airline. If I get miles that I can credit to one of the programs that I am a member of, great. If not, then whatever. I don't have status on any airline, but I can redeem for free tickets on occasion.

Sometimes I factor the value of the miles into the calculation. For example, if I am booking a flight that could get me 10,000 miles on United, I will estimate their value at $100, and I will book the flight that gets me the miles if the price difference is less than $100. But I will only use that logic for airlines with which I have a large stockpile of miles already.

Oh, and I will say that trying out new airlines can be kind of fun.