I bet it is pretty common. Personally, as long as the query is fast enough for my needs I don't care how it executes. I only start caring when performance sucks. I wouldn't be surprised if many other developers have a similar opinion.
And not just in transactional systems but also batch processing, e.g. why would I write mapreduce code if I can just use a system like Hive that gives me a nice SQL-based interface to my data?
Once you learn that DB performance is not a gradual thing, you get into the grove of it. It goes from good to horrible once you hit that magic memory / table size.
Truthfully, if your developers are the ones writing tools to figure out real-time performance, you probably want to start thinking about what's going on. (obviously this does not apply to the parent poster)