It's very rational, it's always been mocked and looked down upon to be optimistic. But through the ages it has been proven to be true that we achieve much more than we imagine.
However the pessimism built in to most people probably helps this drive and is actually a good thing.
Abundance is already here, tons of food are destroyed and thrown out when they accidentally make too much while people are starving, there's no money in abundance, it's the artificial lack of supply that keeps prices high and profits soaring.
I agree but I think their point was more along the lines of "Even if we have complete abundance of everything (as in, the capabilities to produce anything in abundance), capitalists will continue to create artificial lack of supply to continue profiting off of the workers. For example, look at the food abundance we have"
