You definitely can find someone in your late 20s if you have little relationship experience. But you won't be able to make an informed choice and will miss a lot of red flags.
Some of the similarities are insane, like the laser like focus on demographic membership, first impressions, ageism, all the way down to stereotypical trivialities like wailing "there's no good ones left out there" despite obviously living in a sea full of fish.
I'm not sure if its baked into the cake because of something as simple and obvious as the rather extreme gender ratios in HR and Programming bleeding thru into the business processes, or both rituals come from the same larger culture so naturally human selection processes would be similar, or of there's a third more elaborate, probably more interesting, explanation.
I don't think demographic membership and age are invalid criteria when trying to find someone to marry and raise children with. Different demographics have different cultures, and different cultures have different ideals of what is good and bad, how to raise children &c. Age is rather pertinent if one wishes to have children. Even if one wishes to marry and not have children, culture fit is pretty important (and age determines a heck of a lot about culture!).
> wailing "there's no good ones left out there" despite obviously living in a sea full of fish.
In both dating & hiring, the issue is not so much that there are no good options, but that sieving the wheat from the chaff is incredibly difficult. In both cases, so far as I can tell, it's an unsolved problem (or possibly it's solved but we don't like the solutions: I've not quite made up my mind).
Mainly the result of societal pressure or expectations. Being a 33 year-old man, never married. That's "normal". If I were a woman, people would be asking me when I was going to get married and have kids (very much depends on area, but this is not at all uncommon). As a 33 year-old man, it's also not thought of as strange for me to date women in their early-to-mid 20s. The same is not true for women my age.
Then there's also just how people tend to rate attractiveness, which is something that really matters in a lot of these online dating systems. Men are generally viewed as (physically) attractive at higher ages than women are. A few wrinkles on a guy, some gray. That makes him "distinguished". You don't here people saying that about women as often.
The age range and feature-sets for what makes women attractive (again, this is emphasizing first impression attraction) are much narrower than for men.
My experience was different. I was called a loser by more women than I could count because I wasn't ever married by then or had kids.