The wonderful thing about game prices is that they go down.
Are people upset by the $70USD price tag because they want the game day one, but $70USD is too much for them? That's understandable, but it's going to drop in price fairly quickly (which isn't a statement on the quality of the game, just that games go on discount waaaaay faster than they did when I was growing up, that's for sure, where a game would be $50-$60 for a year or more; excluding holiday sales).
Or are people upset because they don't think the game "looks like a $70USD game)? In that case, I think it's incredibly disrespectful to the team at Housemarque and the game to put a price on their hard work because of a 1.5 minute trailer and minimal knowledge of what the complete package of the game entails.
Personally, I don't put a price tag on features/game length/graphics/etc. I care about how much fun I have with the game. Housemarque, in particular, has consistently delivered fun games. Fun games that, sadly, the gaming community tended to ignore, to the point that the studio was in real danger of not being able to create games anymore. That would be a heartbreaking loss for this industry. Returnal is their attempt to marry their game design expertise to a production that is more appealing to gamers.
And now gamers are preparing to pass on the title because of the price, which will inevitably go down, and because of this idea that if a game "doesn't look like it's worth full price" it's a no go. I get people not being interested in the genre (there are ton of genres that aren't my thing), but for me, price just isn't a factor. Not because I can afford it, but because I know, in time, it will come down if I decide it's "too rich for my blood."
In this case, I'm here day one. The game looks awesome, is in a genre I'm actually becoming more of a fan of (I'm generally not into roguelikes/lites, but I've played some really fun ones that have turned me around on the genre), and by a studio I am a fan of, that has a really strong track record for delivering really fun games.
With Returnal being a PS5 exclusive, and releasing when the exclusive library of the console is so low, I think some folks are going to be surprised at how well it does on launch. PS5 gamers are hungry for more games to show off their system, but also games that utilize the system's features (in particular the Dual Sense controller, as now that we've had our hands on it, and have experience how fantastic of a controller it is, it's feature set has been a surprise dark horse in terms of excitement over games that utilize it, and utilize it well - Thanks, Astro's Playroom!).
Also keep in mind that Housemarque isn't a gigantic studio (80 staff isn't really that big). It doesn't need to sell 6 million units to be a success, and I doubt it had a $100 million budget. I imagine it will sell well among the hardcore Housemarque fans, and will have longer legs as the price comes down over the weeks/months after release.
It having a March release date says, to me, that Sony is aware of its market potential, and is maximizing early sales by releasing it early in the PS5's life cycle, when exclusive titles are lacking, and the install base is more likely to buy any exclusive that looks even remotely impressive, and, well, Returnal looks really, really impressive.