Why wouldn't you switch? The cost to switch is near zero for me. Some tools have built in model selectors. Direct CLI/IDE plug-ins practically the same UI.
I think a big part of the switching cost is the cost of learning a different model's nuances. Having good intuition for what works/doesn't, how to write effective prompts, etc.
Maybe someday future models will all behave similarly given the same prompt, but we're not quite there yet
Not OP, but I feel the same way. Cost is just one of the factor. I'm used to Claude Code UX, my CLAUDE.md works well with my workflow too. Unless there's any significant improvement, changing to new models every few months is going to hurt me more.