I'd say that the teens and 22-28 range are hardest for guys, and 28-35 and 65-80 are hardest for women, with college being about equal for both sexes. In your teens most girls cluster their attention on the hottest or most socially confident guys, and from 22-28 guys have to compete with older, more established males for girls that are still somewhat attracted to the trappings of success. But once they get to their late 20s, most people realize that a.) if they want to start a family of someone roughly the same age, they better do it soon b.) the superficial things that most people like in a partner - hotness, money, success, popularity - don't really matter much when you spend every day with them and really get to know them, and what does matter are things like kindness, character, emotional stability, etc. and c.) most of the people who realized this earlier dropped out of the dating pool and got married in their 20s. Women have a much stricter time horizon than guys do at this point, so guys tend to have the advantage in the dating pool.
I've heard dating past the mid-30s is weird, with a lot of divorcees and a lot of folks with baggage from past relationships. I see a lot of age-unbalanced couples in this range, with guys in their mid-40s coming off a failed marriage dating girls in their mid-20s, or single mothers having a string of not-too-serious boyfriends while juggling childcare and a job. Then once you get to 65, guys again have the advantage, because women tend to live longer and so there are a number of widows while very few widowers. I've heard that single guys in retirement communities get so much ass, but for some reason nobody wants to talk about that...
yeah, in other words, they spent their best years on someone else (probably LOTS of someone elses), and now that they're hitting the limits of what their youth/sex appeal can get them, they want some guy with a paycheck who they can slowly mold into a schlub, only to divorce him later.
if you read your post carefully you say the exact same thing, just in 3 or 4 different ways.
if you want to land a good relationship you HAVE to expose yourself to women at an early age and actively work on attraction/improving yourself, or else you're going to be the fucking sucker who picks up the tab later on in life. the illusion of dating being "better" in your 30s is simply women with fewer and fewer choices settling for less favorable selections, which is a recipe for disaster.
the problem is so many guys, especially in IT, are completely CLUELESS to this dynamic and just go all-in the first time a reasonably pretty woman 'chooses' them.
if she wouldn't have dated/slept with the you in your 20s, you sure as HELL don't want to get involved with her when you're in your 30s.
you will never, ever again be in the situation of having so many females vying for your attention. if you squander it, you will regret it.
teach yourself computer science and get a degree in something else like psychology or biology or something.