I very much think this is limited to the startup / work fast and break things style of companies. Always work available for sr. people at large established companies, especially fortune 500. Specifically companies where tech is not the core business product, many of them are attempting to modernize their systems. They pay pretty well too; not Google / Amazon level but on a pure salary basis many probably pay comparable to Microsoft without the shares of course. They do have a good 401k match though. A good salary for 95% of tech people.

I am early 40's and have had no issue finding work and am currently interviewing others to come work with my group in a solution architect / tech lead style role and they are all my age. I have never interviewed for a job and not gotten an offer, regardless of age; with that said I'm not interviewing at startups or places I feel really wouldn't allow me a family life. I get the offers not because I'm incredible, I'm not, but because I know my lane and skill set and stick to it.