The model changes. Robots don't make stuff for workers to consume because there are no workers. Non workers become non-consumers and have no value to capital. Robots are capital and produce products for capitalists. Everyone else fucks off and dies.
The flexible labour market is just the beginning of the end of labour power. Its not a betrayal, but the operation of historical necessity. This is a neo-Marxist analysis - do you not recognise it? — unenlightened
I'm a Green leftie and once knew a fair amount about economics. I don't think the future looks at all rosy but I don't think it looks like your vision in all sorts of ways. One fundamental thing is that yours is indeed a neo-Marxist argument and just like many of them, it's very weak on understanding the 'demand' side of macro-economics. 20th century capitalism defied Marx's predictions by thriving because (a) the nation-state spent a great deal more on non-transfer payments for welfare than in previous centuries, on transfers like pensions, and on the military; and (b) mass markets opened up, in a virtuous circle where better-paid workers bought everything from Henry Ford's cars to Amazon's books. These were the two fundamental sources of vastly-increased aggregate demand that made a lot of people richer than their forebears.
I don't see why there won't continue to be mass markets. As China and other countries advance, their growing middle-classes provide a bigger market. (They're buying up quite a lot of resources in northern England, for instance, where we might have made Manchester great through the invention of graphene) Perhaps short-sighted elites like the British will make their fellows poorer, they look pretty incompetent at the moment, but even on a falling global market, I'd expect a large middle-class to carry on doing well. The end of the Soviet Union, for instance, caused terrible, largely unreported poverty, and a steep fall in life expectancy, especially among men, but it furthered a burgeoning bourgeoisie, brought St Petersburg if not Moscow back into the great European cities, and no collapse of civilisation was reported, even though the effect on the rural poor was in my view disgusting.
If you look at economics through an ecological lens, which I've taken to be the better lens as I've got older and understood more, then there are profound (as apo would say) constraints, and it remains to be seen how they will be dealt with. Fossil-based energy gradually runs out, rare metals get rarer, so you can't keep making toy phones in such quantity, and you can't drive this many cars on solar power, so major structural change will occur. Climate change kicks in so there will be big climate events, though I think poor Bangladesh is in bigger danger than London, the metropolitan elite are quietly spending a fortune on making London safer (
see this on how the South East has most flood defence spending). I daresay other metropolitan elites are doing the same.
What's to be done? Me I'm just plugging away, putting Green leaflets through doors (though it always seems ironic to use leaflets), doing my bit for civil society, conscious that long-term predictions are usually our present fears or hopes writ large, and bugger all to do with how things will turn out. And really, my lifetime has been pretty good: relatively peaceful, affluent, free. If we can pass some of that down the line to our grandchildren, that's the best we can do. Alarm stokes up populism and motivates only despondency.