because what they can offer isn't valued by capital

People categorize people as 'useful' and 'useless'. Hell, get down to Biology 101 and mate selection, animals select useful against useless. What do you have to offer?

"I'm having a heart attack! Help!"

"I'm a really nice guy that does wonderful paintings of the local pelicans!"

"Fuck off, I need a skilled physician and I'll pay anything right now!"

Yes, people get paid more or less dependent upon their use to society. Why would society support you if you have little, or nothing, to contribute? For those of us in first world countries, we're populous enough and technologically advanced enough to support a wide range of talents. Of course there are plenty of counter examples, but that's mainly how it goes in any given economic or governmental framework.

tl;dr: We're social animals with needs. Fulfill needs or GTFO. You don't have to like it, but you better understand it.

This is too involved a topic for a thread like this, but the red scare propaganda we learned about the Soviet Union isn't a complete picture of how things were there. From researching around, it seems like at least on the dietary front, their caloric/nutritional consumption was comparable to the US, although there's some variation in the estimates of different researchers/institutions. Sure, they didn't have Macdonalds or Pineapples and stuff like that. But not having shitty unhealthy fast food and a fruit that could only be as widely available as it was in the west through imperialism isn't exactly what I'd call a poverty stricken hellscape.

As far as recovering even now... there was a really important thing that happened between then and now that's had an impact on these countries: privatization. Sell off public goods to private interests so they can profit off them at the expense of everyone else. And surprise, like we see everywhere else, private businesses don't act in the public good and only occasionally, incidentally produce results that are good for everyone.

Like I said though, it's a really complicated topic that's worth reading more on if you genuinely want to learn. They didn't do everything right, but these communist societies managed to rise out of feudal or colonial systems to become modern industrial powers despite all the forces aligned against them.

As for capitalism, even if it can produce great abundance,

a) That isn't actually benefiting the vast majority of people. It's hard to overstate how cruel it is to have people going hungry in a country that can produce so much food it throws a lot of it out with only like ~2% of it's population working on a farm.

b) Like I mentioned earlier, a lot of that abundance isn't merely from free trade and the ingenuity of industry. A LOT of it is built off the exploitation of other countries and the over-use of resources to the point of causing environmental damage.

Whatever you think society should be like, it isn't hard to make a less cruel, less environmentally destructive, and more inclusive system than capitalism.