I don’t think in my case that it was necessarily about
me and my performance. Just like I don’t think that the OP’s story is necessarily about him and his performance. When teams grow, they change. There is an all-too-often unspoken assumption that roles will get more and more specialized as the team expands. You can go from being a dev/pm/architect/analyst to being “just a dev” or “just an architect” so slowly that you don’t even notice the de-facto demotion until it is too late.
A metaphor I use with management to prevent this from happening again is “I eat my broccoli so I get to eat my ice cream. Hiring someone to eat ice cream for me so I can focus on just broccoli might make intuitive sense to you, but will have a detrimental effect on me”