“What counts as treats and what is necessary requirements” is a fun question. Two relevant Engels letter excerpts:

The English proletariat is actually becoming more and more bourgeois, so that this most bourgeois of all nations is apparently aiming ultimately at the possession of a bourgeois aristocracy and a bourgeois proletariat alongside the bourgeoisie. For a nation which exploits the whole world this is to a certain extent justifiable Engels to Marx, 7 October 1858

Becoming more bourgeois ofc means that it consumes more, has more treats, etc. So to Engels (and Marx didnt disagree), but 1858 some portion of what the proletariat had was already treats in their eyes.

Another letter is Engels to Kautsky, 12 September 1882:

You ask me what the English workers think about colonial policy. Well, exactly the same as they think about politics in general: the same as what the bourgeois think. There is no workers’ party here, there are only Conservatives and Liberal-Radicals, and the workers gaily share the feast of England’s monopoly of the world market and the colonies.

So by 1882, Engels re-asserts more strongly his 1858 beliefs. One wonders what he would have made of the post-1950s (i.e. post great acceleration and consumer society) workers in the global north. What does this mean in terms of political action? Marx’s letter to Engels from 1869, December 10 may shed some light:

The way I shall express the matter next Tuesday is: that, quite apart from all ‘international’ and ‘humane’ phrases about Justice for Ireland — which are taken for granted on the International Council — it is in the direct and absolute interests of the English working class to get rid of their present connexion with Ireland. I am fully convinced of this, for reasons that, in part, I cannot tell the English workers themselves. For a long time I believed it would be possible to overthrow the Irish regime by English working class ascendancy. I always took this viewpoint in the New-York Tribune. Deeper study has now convinced me of the opposite. The English working class will never accomplish anything before it has got rid of Ireland. The lever must be applied in Ireland. This is why the Irish question is so important for the social movement in general.

So in summary: Marx and Engels would likely look at a lot of stuff we consider necessities as treats, but neither give any hard prescriptions. Marx by 1869 seems to have realised that treats from colonies/imperialism were perpetuating the system and so believed that the English working class needed to be rid of Ireland (I would assume india, etc too, but that wasnt the focus of the internqtionale meeting) before it could accomplish anything.

Edit: regarding what the capitalist cares about, this will be revealed throughout the book (startijg especially in ch10)