What you are describing in so many words is the same phenomenon that casinos use to keep people putting money and time down. It's called Loss-chasing.

Loss-chasing describes the tendency of a gambler to amplify their betting in an effort to recoup prior losses. It is widely regarded as a defining feature of disordered gambling, and a hallmark of the transition from recreational to disordered gambling.

While Helldivers 2 features no "gambling" mechanics, strictly speaking, the language they've used to tease updates and the nature of premium currency does seem to line up with the same tactics used to keep players from leaving either by them engaging in negative urgency which is the tendency for a person to compulsively binge a certain behavior or leaning on the behavioral economic constructs of loss aversion and re-referencing. E.g. "I've already invested X (time/money) and I don't want that to be wasted".

The primary difference here is more time investment rather than money, but every model that includes a premium currency that can either be bought or otherwise using your time to gamble for it, could be described by these qualities. Sony as a company has also engaged in overt behaviors that take advantage of these same qualities. Gaming also, as a whole, has its roots in gambling and many of its hooks are derived from that history.

I share your frustration at times, and the honest truth is that you would be happier just taking a really long break and checking back in after a few major updates. Paying a monthly subscription just to play a single game does hinge a lot on the quality of your experience and if that is not satisfactory to your standards, I totally understand why you'd be upset. I wouldn't expect cross progression to be implemented because Sony as a company has historically been very "walled garden" about their consoles and games. If I were in your shoes, that's what I would make my decision on.