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.
In my experience, to get the best performance out of different models, they need slightly different prompting.
There's a plugin for everything that mimics anything the others are doing
I see all of these tools as IDEs. Whether someone locks into VS Code, JetBrains, Neovim, or Sublime Text comes down to personal preference. Everyone works differently, and that is completely fine.
I'm not sure you even understand what opencode is.
Maybe someday future models will all behave similarly given the same prompt, but we're not quite there yet