If you're doing 10+ interviews a week, likely you work in Big Tech. And that means several things have happened before you even interview a candidate, specifically screening by ATS, AI systems, recruiters and hiring managers. There are perverse incentives (eg recruiters putting people in the pipeline to boost their numbers) and there's also massive discrimination, particularly age discrimination.
Tech companies in general want to hire grads or near-grades in vast quantities, particularly from the more prestigious US colleges. You get to 40 and suddenly you don't make it through those initial pipelines before you get to interview the candidate. They're not suitable in some way. And over 50? Forget about it.
And if you do make it through these filters, you may still get filtered for not being a "culture fit", which is just code for "not like me". And if the employee pool already skews young, male and from those same colleges, "culture fit" is just a thin veneer that reinforces discrimination.