I don't think MCPs have legs long-term, but they are a great middle ground during this somewhat turbulent transition period we find ourselves in, precisely because they are not the existing tooling (they are greenfield).

An existing company that has an API/CLI might not have everyone on the team on-board with LLMs and agents and what have you – it might be hard to get buy-in to modify those existing surface areas to be more "agent compatible".

Meanwhile, a team within a company that wants to make their company more "agent forward" can build an MCP tomorrow and it is clear what it is for: is a new surface, meant to be consumed by agents, with the needs of agents top-of-mind. It avoids confusing interop issues with existing tooling while maximizing said teams ability to ship changes/experiments quickly.