Things aren't adding up because what has been said in the past wasn't really true. It isn't obvious at all that someone at Nintendo figured out that communication with western developers is important, because aside from Bethesda there is barely anything else coming to Switch. Electronic Arts, Ubisoft, Warner Bros., Activision... their IPs are largely missing and it doesn't look like that will change. This leads to the conclusion that Nintendo hasn't changed, but rather that Bethesda has changed.
Bethesda couldn't say that technology difference is the reason why they weren't bringing games to Wii U, because at the time their games were made for PS3 and 360. That's why they overexaggerated something else to direct the blame to Nintendo, and at the time of making that decision they couldn't say "Wii U sales" because the console had yet to launch. Ultimately, their reason not to make games for a Nintendo console was as simple as "we don't want to," but such honesty would generate bad PR for them. That's why third parties in general jumped back and forth between their reasons for not making games for Nintendo consoles, because it's not always the same excuse that is the most convenient one.
Conversely, now that Bethesda is making games for Nintendo, they overexaggerate how good their relationship with Nintendo is because it's good PR. What has changed over the years is that development times have increased and companies need to adapt to it. Western AAA third party publishers have shifted their focus towards online multiplayer and microtransaction to increase their cashflow, but not so Bethesda who still value single-player games. Such a direction necessitates that all platforms get serious consideration, because releases on more platforms mean more cashflow while The Elder Scrolls VI and others are in lengthy development. As such, the "we don't want to" changes to "we'd like to" because that makes it more manageable to continue to make the games they want to make.
Similar observations can be made for various Japanese third parties. There are too many inconsistencies to believe that Nintendo has changed in a significant way, rather it's the changing circumstances in game development and the video game market as a whole that made third parties rethink their stance towards Nintendo consoles.
You're going to believe what you want but I absolutely believed Pete Hines when he he talked about Nintendo at E3. That was as honest as I've ever seen a PR guy get. In my opinion, that was real. He meant what he said then, even if he had to cover it over later.