How awful if someone’s children are complete arseholes to their parents but will still inherit money from them.
Well, but imagine the alternative: I have been nicer to you, so I should get more than my siblings. Oh, is that why you were nice to me, because of money? How awful. Or, the parent rewards one child more for bending to their wishes, which may or may not be completely unreasonable, (marry this person, not that; don't be gay; I don't like people of a different ethnicity/religion, bend to my will or you're out) punishing the others. It's the plot of King Lear, and that didn't end well for anyone concerned!
At any rate, such provisions don't rule out unequal divisions of property. They simply assert that you owe something to the children that you, of your own free will, brought into the world. And if they are arseholes, well, maybe that has something to do with you, as a parent...
None of this is the OP's hypothetical case though. Their question is whether the profits from a portion of wealth that has been inherited rather than earned should be passed on in the here and now.
It's an interesting question, but the OP's position seems to boil down to thinking the family pie comprises 'what you really have because you earned it' and 'what is there to be sliced into by your offspring whenever the need arises, because you only inherited it.' I think there are ways of ringfencing wealth into trusts so that it can be preserved rather than spent, (although I guess there has to be a beneficiary of a trust, and sooner or later the property can be accessed somehow) and presumably this option was open to previous generations. So either they didn't know they could do this (shame) or they did know, and didn't care to do it.