except other than new powers which the expansions offer there is little to be gained by playing any expansion before the most recent as the gear you get will be useless once you hit the current expansion.
That's not true at all, there are plenty of old guns and pieces of gear from previous expansions that are still great guns.
Not to mention it's a game... Playing the campaign itself, learning the story, etc, is something to be gained.
Not to mention all the vaulted content that you will never get to play.
And you're not paying for that... Everything that was vaulted is no longer charged for or charged for at a significantly reduced price (e.g. the Foresaken pack for exotics). The prices on old content (even the sticker price) also drops over time.
No it's not a cheap game. Yes it's free to play, and then you need content expansions to really unlock the whole game. Destiny is free to play in the old school "free to play" sense. It's free to access some content and do some stuff with your friends then you either buy expansions (the route Destiny and WoW went) or you pay a subscription (the way RuneScape) went. These are very old models and they're not scummy in the slightest. They're the moral equivalent of a free trial.
We literally just brought someone in, unfortunately the best way to do it is to wait for a sale. It's ~$20 for the majority of the old content (legacy 2023), ~$15 for bonus content (armoury collection -- what's left of foresaken and the 30th anniversary celebration DLC), ~ $40 for the current expansion and season pass (lightfall + annual pass), and I think a fixed $10 for the 2022 dungeon key.
That's $85 for the better part of ~4 years of game content/development and ~4 more months of yet to be released paid and free content.
Then yes, $100 for next year (which if it was a subscription would be <$10/mo). To put that in perspective, if bowling was your hobby, it would be significantly more expensive. We're all adults and can afford it... No harm is being done and it's all in all a good deal for the hundreds of hours we've spent in the game.
micro transaction give you easy access to all the best cosmetics which is quite manipulative at its core.
Cosmetic micro transactions where you know exactly what you're getting are again not a problem.
Types of mechanics used to trick money out of players
I didn't watch the videos (I don't even watch long videos friends send me half the time) but I skimmed the articles. The first is just some person's blog not exactly "research worthy." It's also not talking about what I've been talking about (i.e., if you just bought a $70 game you didn't like, you haven't been tricked, just refund the thing and/or don't buy it).
The second is much more credible as a source, but they're talking about loot boxes and gambling mechanics... And yes, those are a problem 100% (especially in mobile gaming, but also definitely Relevant in things like CSGO and as you mention Diablo, and also these days, RuneScape 3) but they have nothing to do with Bungie/Destiny 2 and they have nothing to do with people buying the Call of Duty base game despite its numerous issues and horrible reviews ... and then also not refunding it ... and/or buying it again next year.