I'd say for some sectors and users, we're already seeing that. After GLM-5.2's release there were quite a few stories about it picking up use.

Then looking at Openrouter's stats we can see heavy use of non Anthropic/OpenAI models https://openrouter.ai/rankings#top-models

I'm not sure I'd call them rando, but Deepseek/Qwen/GLM all have decent models that will work fine for some use cases at much lower costs that the SOTA models from Anthropic/OpenAI.

Exactly. As soon as business works out that there are open models that can achieve parity at a fraction of the cost, they will switch model. They have to. Business exists to make money, and if they can do the same thing at lower cost, they will.