I agree with a lot of this. There is a slowdown in my reaction speed to say an incident or a bug or a feature design. But I have so much knowledge and context

I agree with a lot of this. There is a slowdown in my reaction speed to say an incident or a bug or a feature design. But I have so much knowledge and context built up already that when I do respond, the execution is much better and leads to success (success == incident fixed, bug fixed and design fully implemented/executed and makes money). I genuinely think that companies who don't hire older engineers do themselves a disservice. No wonder only FAANGs sustain themselves over decades, not the one-hit wonders from silicon valley.