As a counterexample, I have also authored both assembly and CSS professionally (not at the same time), and I chose to completely abandon web development after endless battles with kludgey, inconsistent CSS vacuumed all the fun out of it.
(I imagine the situation may have improved over the last 15-odd years, but I'm not going back in to find out.)
I still enjoy assembly programming, though opportunities to use it have become a very rare treat.
I've done both CSS for about 26 years (since its first release) and Assembly language for about 35 years, and I love both of them - for different uses and different reasons. They are both great for the job they were meant to do. I even once wrote a JSON parser/serializer in 8-bit Assembly so the embedded device I was building could easily communicate with the browser front-end I had built. It was all pretty fun to me.
(I imagine the situation may have improved over the last 15-odd years, but I'm not going back in to find out.)
I still enjoy assembly programming, though opportunities to use it have become a very rare treat.