I think your question is an interesting one (for reference, it was regarding whether budget decks could be more successful and significant portions of the vintage metagame if picked up by skilled Vintage players).
Speaking as a general principle, the odds of having a restricted card in a 7 card hand is 11.6%. Depending on the deck, you are typically giving up at least 2-4 restricted cards (Lotus and on-color Mox for non-Blue decks, these plus Ancestral and Time Walk for Blue decks like Delver/Landstill). That ends up being 22.1% to 39.9% of hands that you are sacrificing the ability to have one of these very powerful cards. If you consider mulligans, additional draws throughout the game, and that with the London mulligan, you are always seeing 7 cards (and so these percentages are constant throughout the mulligan process), that ends up being a substantial impact on your matches. When there is no structural incentive to make this deckbuilding change, you are highly advantaged to include Power.
I would also challenge the notion that the players running budget decks are unskilled or that the decks traditionally considered budget have a high enough ceiling. Players new to the format might have experience with Eldrazi, Delver, Merfold, or other budget options from Legacy - and their knowledge of Magic as a game might be higher than some Vintage players based on the more competitive play in other formats. These decks have Powered variants and you find that those Powered versions are not substantially stronger in the metagame compared to the unPowered versions. It normally boils down to some structural disadvantage that hurts the viability of the deck.
To expand with some of my experience in collecting Vintage data, Vintage Champ from several years ago showed that Eldrazi, whether Powered or unPowered, White or Colorless/Jaco, struggled against Workshop decks. I believe the win rates were sub-20%. The intrinsic disadvantage was the manabase as Workshops produced more mana that could cast more relevant spells than Eldrazi and the Aggro variants could better leverage the tempo of their Spheres and Wastelands. Eldrazi could steal games with Null Rod and Thalia, Heretic, but percentage-wise it wasn't enough.
The problems have been compounded recently. Workshop decks have gotten better threats in Stonecoil and Golos, but also Bazaar, which used to be very exploitable by budget decks as they typically thrived on Wastelands and hate, are typically outclassed by the clock from Hollow One and Co. Power in the form of Moxen and Lotus becomes necessary to compete with Tempo advantages of Bazaar and Workshop. Again, I draw on my own experience brewing with Humans and Maverick. You want the possibility of those Lotus/Moxen hands for when the opponent has double Hollow One starts or Sphere draws that you can't get out of by playing a land a turn.
I'll straight up admit I don't have the experience with the data you have. My understanding is that the last two years with paper champs (2018/2019) showed eldrazi with around a 40 OMW% and the best performing blue decks at well over 50. I understand its very possible that people played eldrazi at their LGS religiously and have a lot of experience with the deck, but I expect that it is more likely that people who want to play at champs and cant buy or borrow power would play this deck (and subsequently do worse than a blue deck).
I'm completely with you that skill in one format can translate into other formats. That's how competitive magic works.
I also agree that the meta does not favor jaco eldrazi, If there was a dedicated jaco eldrazi community that might change. Or it might not. Building a budget deck is like trying to play a block deck in standard, the cards are legal just worse. Theres no competitive reason to build budget, and people are doing fairly well with white eldrazi.
It would be interesting to see someone put a lot of effort and time into budget eldrazi and see where that ends up. Or budget anything.
I think there's an overlapping area where suboptimal and budget meet. But I think that designing a deck so that it costs what a modern or legacy deck costs would be considered budget.
Even at that point that would put the deck well out of most people reach.
It was a main deck null rod build that tried to fix some of the issues that the deck had with top decking dead by removing the mana artifacts. The meta at the time was generally quite soft to the rod so having 4 main deck you could play without worry or hesitation was very strong.