You are fundamentally misunderstanding the point I am making. LLMs have repeatedly started with training wheels and then slowly had them taken off as they have become more and more competent. MCP is another example of training wheels that will likely eventually go away. If the direct web/API calling abilities of LLMs were to improve with better trained models and some more built in support then MCP could go away and nobody would miss it.
No, you are still not getting it. MCP will never go away, or at least something like it will always end up existing.
What you are describing, "web api calling abilities were to improve" will not change anything. What sort of improvement are you thinking of? They can only get better at outputting json correctly, but that hasn't really been a problem for a long time now.
Either way, it wouldn't change anything, because MCP is a 100 other things which doesn't have anything to do with the llms using tools directly. You will never embed everything that MCP can do "into" the llm - that barely even makes sense to talk about. It's not just a wire protocol.