I do hope that Cursor doesn't remove any of its current model offerings, and just offers Grok Build in addition to what they already offer, in my opinion unless most of their clients "switch" to Grok (like metrics show they're mostly using Grok vs other models), it would make more sense.
Enterprise AI adoption has reached a point now where FinOps matter, and a harness platform story with a discounted underlying model can be enticing for a number of organizations.
I've seen Gemini land well in a F100 well known for their AI hardware story for that reason, and Alibaba's leadership canned the OSS minded Qwen team in order to build a similar commercial minded approach as well.
At least in cybersecurity, we're also reaching a point where the harness is starting to matter more than the underlying foundation models, and building a harness/bedrock style story while discounting a specific model can play well in upper market deals.
There is a recognition that foundation models and tools leveraging them will introduce some degree of nondeterminism, so the best way to solve that is to leverage preexisting best practice that is used to reduce lateral movement risk by humans (who are similarly nondeterministic in nature).