Simply look around any tech center company and look around. It’s mostly younger crowd. The graybeards are few and far between and in mostly few senior roles.
Even transferring to middle management doesn’t help much. The same type of younger crowd are brought in to keep up the appearances. The olds are few and far between in director and up roles.
It’s simple reality that happens, there’s an age cutoff, and it’s not as old as people think. It’s definitely not the official retirement age.
Keeping up with latest tech stack helps. Moving up the seniority levels helps. Moving from company to company helps.
Entrepreneurship helps, you as owner can hire yourself, but you’ll most likely hire younger people for your company, which perpetuates the ageism cycle.