When it comes to strictly logic and the way Kishi likes to divide powers.
Hagoromo = master of using chakra
Hamura = master of destroying chakra
Hyuga could never match Uchiha because we were doing the wrong comparisons most of the times, the talent of Hinata's clan doesn't lie in ninjutsu, it lies in the ability to counter ninjutsu. On the other hand, Sharingan is the ultimate tool for ninjutsu.
It'd be true, only if the user has all the characteristics of Hamura, which a pure hyuga doesn't. It's like saying a base sharingan user can use Izanagi perfectly, even though only a Wood release working in conjuction with Sharingan can make use of a perfect Izanagi.
Hyuga as a whole is just one half of this whole ancestral household of Hamura. Otsutsuki is the other half.
Just like the sage's descendants are divided into Uchiha and Senju. Now, saying Uchiha feats is equal to Senju is illogical, isn't it?
Edit: I see you edited your post, it's clearer now.
But you see, Plot is not the answer. Plot can be said for anything. Instead of claiming plot, the more logical method is knowing or trying to understand why things are the way they're.
Gates are totally different things, they're not the opening of Chakra points, they're the opening of certain "Gates". This is like exchanging feats among clans, it's almost hilarious imo. Its like me saying, Senju is brother of Uchiha, so they didnt get powerful eye power to manipulate Bijuu so it's plot.
You look how funny it is? How hilarious and how endless this logic is? Otsutsuki + Hyuga = Hamura, Otsutsuki feats =/= Hyuga, Hyuga feats = Hamura, Hamura feats =/= Hyuga feats.
So this roundabout logic ends nowhere. Literally nowhere.
If opening gates are so easy, Might guy wouldn't be the only individual, uptill the War era, to open and master all the Gates imo. If it was that easy. It's called celestial gates for a reason, not "Chakra gates" like "chakra points". They're totally different things, no matter how similar it sounds. To make it worse, Might gai was the Sensei of Hyuga neji, the most genius Hyuga ever born in the Clan imo. If Neji could achieve that power, Gai would've willingly taught him imo.
And even by your hypothesis, which do make sense in the logical manner, it's disaproven by the manga, by Hashirama's statement, who said no one clan would be capable of facing them if Madara and Hashi and thier respective clan team up.
Keep in Mind only Madara could use Susano'O at that point and only Hashirama had Mokuton.
If we follow plot logic, Senju clan would be the weakest clan, considering how broken Hyuga taijutsu style is, even then Hashirama didn't even care to keep them near thier level, not even close.
So as the series is now, Senju and Uchiha are established as the Strongest Clans. Thier is no changing that. No matter how skilled a hyuga is to appear, he/she'll never outmatch an Uchiha with a Susanoo. Unless he/she gets the ancestral power of Hamura's direct chakra and power. Hyuga's power alone is not enough. That fact is far by now, clearly and unchangeably established by this Manga.
Even if we're going by the past surpasses the future logic, the War alliance Shinobi were clearly amazed by Hashirama and Madara, so it's clear that some levels of power and status will never be surpassed unless some certain conditions like Ancestral transmigration helping a certain person reach those levels of height takes place.