The people who find candidates to interview are not the same people as the managers who decide who to hire. The fact you're getting lots of recruiters chasing you just means recruiters don't discriminate on your age; it says nothing about the hiring managers.
Perhaps this means that as a 40+ year old developer, you're more likely to get a job if you go through a recruiter, as opposed to sending your resume off on your own?
My spam folder says otherwise. There are still enough bad recruiters out there (or bad recruiter spam-bots) hitting me up for positions that don't remotely match any skills I've ever listed anywhere. Not worth my time.
As someone who gets sent candidates by recruiters, I don't think this is true.