I don't think you can have it that way - the point of a critique is that it is some positive development, a hint or suggestion at a possible world without those

I don't think you can have it that way - the point of a critique is that it is some positive development, a hint or suggestion at a possible world without those things. If Marx criticised capital, abstract labour, etc. then we take it to mean that socialism would not have them. If they were fixed parts of all human society, then Marx's critique would be nothing more than an empty complaint, no different to arguing with gravity over a broken vase. But as the Schweickart quote shows, there's no immediately obvious way to go about fixing it, once we admit that (1) there is a problem, (2) the problem can be fixed. It's a mistake to think that Marx thought revolution is the only way to abolish capital. But it's also a mistake to characterize him as a reformist.