Untold hours are spent by web designers and developers to make sure their creations work in different browsers and platforms. They may curse and mutter and otherwise cast aspersions upon the creators of various browsers - in fact, I think it's in the job description - but they do it.
They research and experiment to learn workarounds, which are then used on their future work. All this is to be sure as many people as possible have the best experience using the website.
On the other hand, accessibility is seen as some special extra feature that must be cost justified, and then isn't addressed because it is "too hard" so it "costs too much".
Accessibility is no harder and no more expensive than any other part of web development. Everything is hard and expensive if you don't know how to do it, and it's not hard when you know how. So learn how to do it, just like you learn to do anything else on the web. There is no shortage of useful information on the web; for instance, here's a place to start: WaSP InterAct Curriculum: Accessibility.
If you can't be bothered to learn what it takes to make websites accessible, then don't bother to call yourself a professional.
Note: Accessibility means making sure your sites work for people who use screen readers, speech-to-text software, specialized hardware, and other adaptive technologies. It means taking into account color-blindness and eye fatigue. It means taking into account people working in noisy rooms and moving vehicles. All told, accessibility features accommodate the needs of up to 20% of your users, and perhaps even more.
(Cross-posted from Too hard is the worst excuse