Is "too experienced" the new ageism?

I applied for a job recently which would have been a slight step up the career ladder. The job was excellent and I was really excited about applying. I tailored my CV accordingly the agent liked it and thought I was a great match and after 2 weeks the company reported back that despite my impression that it was a step up the career ladder and it was a bigger package than I am currently on that they rejected me because they felt I was "too experienced".

Is this a euphemism for "too old" I wonder? I don't feel too experienced when shovelling horse shit each night when I clean the stable. I don't feel too experienced when I do the manual work around the house. I also don't feel too experienced being versatile enough to step in and do all sort of work that comes my way so long as it gets the job done for the company?

Too experienced? Is there such a thing? If I think I'm a good match for the job, the agency thinks I'm a good match for the job is it not better for a discussion to happen regarding whether the employer feels I'm too experienced or not rather than a flat rejection? After all, what some women prefer when returning from having a baby is an easier job with more flexible hours, less stress and a better work-life balance. Are they also rejected for taking a step back because they are "too experienced" ?

Well if the company wants me to run a multi billion pound company then fair enough I'll take the job, but really being a project manager would be just fine for me thanks. It would be a great job, would be a career move for me and would allow me to balance the day job and doing an MBA. Perhaps after 2 years I might be too experienced then, but 2 years is a long time to look around for a promotion.

My experience, as well as feedback from agencies and the experiences of other candidates indicate that recruitment is easily the most inefficient process when running a business. How can it be made to work more smoothly?