I don't believe it's random.

Well, my collection shows opposite results so there's that. Shun the nonbeliever. Shuuuuun.

This doesn't make much sense. IVs are the same for all trainers above level thirty, as already stated, so if there was some Pokemon with consistently lower IVs, it would be lower for everyone above level 30, not just you. I'm sure that every high level player has some species they've caught thousands of and never gotten a 96+ - the odds that they have a very good IV instance of every species is very low! Hence, they could come on here, make the same argument that you did. But then with enough level 40s doing so, it would seem that all Pokemon have nerfed IVs, which we know isn't the case. Even with 4096 IV combinations for a wild caught Pokemon, it is highly unusual that you have yet to catch a good Venonat - I'm sorry about that. But, if you save them up and trade them with a friend until you get a few luckies, you have a great chance of getting one over 91% and with half the stardust cost to power up.

I get how you feel. I can get any amount of 90%+ vulpix from research but for the love of me i never got a 90%+ houndour. We want to see patterns everywhere since randomness is not in our nature!
My personal theory for example is that heavy paying players (like a guy i know that constantly floats 100 premium raid passes at any given time) get at least one guaranteed shiny during an event (they may not catch more than 2 or 3 ,but always at least one of each) while non paying players tend to get a lot of one species of shiny but miss some others (like getting 5 Cubone but 0 ponyta during the last event).
Of course my sample size was my group of friends and i was really pissed i didn't get the shiny Ponyta myself ^^. All in all i think it's mostly RNG but since Niantic is very shady regarding the inner workings and some mechanics of the game (like lucky trade chance or shiny chances in raids) and most trustworthy info has come from research done by the community, it's very difficult for Niantic to face criticism like the one you are making here with something more than "it's just RNG". Don't think too hard about it since there won't be a sollution anyway and you will just get salty (and most RNGs are not truly random anyway since usually to program them you use a seed/base value as starting point to simulate the randomness)

For me Starly, Nidoran M, Chimchar, Solrock, Houndour and Buizel are the hardest to get good ivs on. I think some specimens are supposed to get bad ivs instead of higher ones.

Obvious troll.

"Convince me otherwise, and unless you wrote the code or control the servers, I'm not buying what you're selling."
Aight dude... you realize that NONE of us work for Niantic right? You basically just posted a rant and then outright stated that you don't respect the community's answers as valid.

I'm a career programmer and chronic TCG player (such as magic and HS). RNG performs things all the time which can seem miraculous. I'm also relatively educated in statistics and I can tell you this: While your data may point to one conclusion (that gen4 mons have a higher hundo rate than venonat), you CANNOT ignore the data gathered and presented by the rest of the community. That's not even statistics. That's just selectivism with the goal of proving your point. If corporations could do that with medical case studies we would all have died from unsafe antibiotics only years after they were released.

Here's what I can say: I have two hundos: A kingdra and an eevee. The kingdra was a wild catch. The eevee came from a research task reward. After these two, my highest IV mons are meganium (from chikorita CD), Mewtwo (from mewtwo raids), machamp (from the gen1 mon appearance boost event), metagross (from beldum CD), various eeveelutions (from research tasks), Gengar (from gengar raid day), assorted legendaries (from raids and research rewards), and a couple of luckies from trades.
If you don't believe me go check my box. I uploaded it to gamepress and keep it current (with my best mons. I don't care enough to upload and track the trash).

In other words: My highest IV mons all either come from increased spawn occurance events (which increase the likelihood that I'll encounter them and by proxy that I'll encounter a high IV mon) or from raids/research/eggs/lucky trades which all guarantee high IV mons. The ONLY outlier is a Hundo horsea turned kingdra. Your gen4 hundos come from their spawn occurance boost event I'm guessing? If so, that's EXACTLY in keeping with my findings. You get high IV mons from events where either their spawn rate is boosted or their IV's are guaranteed to be high. You get significantly fewer high IV mons from just walking around and finding them randomly (which is the only way to get venonat/venomoth).

There's your stats. You have more hundo gen4 starters because you've seen more gen4 starters than you have venonat/venomoth. It's that simple.

Unfortunately I don't have access to the game's code/api files to prove this to you, nor am I about to try to obtain those files illegally, so do with this response what you will.

OP needs some basic Probability of Statistics knowledge.

Most likely none of us here was coding the game, but Silphroad has been studying the game mechanic all the time, including the ratio you mentioned, and according to their research (usually done by gathering information from thousands of players and data mining) they have not found any trace of artificial influence on the RNG, so your point is invalid.