Perhaps, but I can say that I am over 40 and I can tell when the enthusiasm for my candidacy dies after they see my face that it's not due to anything but ageism.
Like I said, not to invalidate anything, these experiences are so common amongst the whole pool that it has to be weighed accordingly.
(Not everything people say online is true.)
It wouldnt take me 700 hours to get familiar with all the abstract problems and concepts I’ll encounter, but it would take me a very long time to, and longer to synthesize solutions that are above average, and regurgitating that on the spot for an interview in a quicker time than other candidates.