One thing for certain, Microsoft will not stop using Copilot to develop their software in house.

You're wrong, but I think you'll be OK with that because the reality of the situation is actually hilarious:

https://www.theverge.com/tech/865689/microsoft-claude-code-anthropic-partnership-notepad

"Turns out Copilot sucks so let's just use our competitor's superior product but that's no reason we can't keep foisting the inferior garbage on the masses!"