There's another perspective on this: Someone who has reached (via promotion and not via nepotism / acquisition / external hiring) GL 11, 12, 13, 89, 90, or 91 (those being, in order, Tech Lead I, TL II / SW 5, PE, DE, and Fellow) are, or were, good at innovating internally or leading large, complex development projects. That's why they were promoted. Yes, their paths may have been made easier by a mentor, or a friendly VP, but reaching that level took time, during which the employee grew up.
Large, complex projects require budget. When is the last time anyone saw a large, complex internal development project funded and carried forward to completion? There is a ton of money for acquisitions and spin-ins, but not so much for internal development.
So what do senior technical staff do in the absence of internal development budget? Fix bugs? Add features? If you are a VP or Senior Director and have a headcount limit to enforce, it doesn't take deep management skills to figure out that a GL 8 might fix a bug or add a feature (pick your fraction) as effectively as a TL II, at a vastly lower cost. So why keep the TL II? That they happen to be over 40 or over 50 is a coincidence.
I saw lots of opportunity for innovation and product enhancement, but it was obvious that the chance of funding internal development was zero. I wasn't surprised when I got the meeting invite, nor do I regret it happening... Rome was big and it took a long time for it to burn.