This is one of the reasons I'm eyeing management for long term career growth. I've learned that the problems given to sr. and jr. engineers are roughly the same, and that the interview process is biased towards jr.
True, also the industry prefers younger population coz they can burn more hours and are available for a cheaper than the experienced folks.
Also, the industry somehow seems to stereotype a developer as some younger geeks. The stereotype works against experienced folks sometimes (not always).
If we had a sane choice we would still stick to tech - tech is like the first love that is going through a rocky phase!
I believe there is the "collective stupidity" problem in the tech industry where a new framework pops up almost everyday, a new language every now and then and the sheer volume of knowledge to accumulate to stay relevant is abysmally high! With the realities of life taking over, the path is inevitable to most senior people.
I think you're underestimating how hard interviewing can be for new grads. There are some that are good and others who lack the background or the confidence.
It also seems a bit weird to give senior engineers easier questions. Do you really think people get worse with experience?
I think the skill set changes with experience but the problems given in interviews don't vary much. For example, a fresh grad is more likely to be able to correctly implement merge sort from memory than a sr. engineer because of how recently they were asked this problem before. Whereas a sr. engineer should be able to better think through "soft skill" problems like estimations, expectation alignment, and how to deploy complicated changes with little impact to the business.
I've come to learn coding is the easy part. Where it gets tricky is when you introduce other people.