Even if it were true that is not the problem. Even sucky devs can crank out code that runs reasonably fast. It just depends on whether the company sees it as a required feature.
Making your code run quickly will not help if your software architecture is inefficient or optimized against the customer as so many web applications are these days, for example. There are many commercial web pages that appear and approximately ten seconds later clicking on a button will actually do something. I am not sure why that it considered acceptable, but customer experience doesn't seem to rank very high on the list of priorities.