If there is a dire need for potato-picking manual labour, pay will increase, as will the price of potatoes, short-term at least, assuming the change is sudden and of immediate effect, which makes the scenario even more unrealistic. Realistically, rather than labourers becoming indefinitely well-paid, and potatoes indefinitely expensive, alternatives to manual labour will rapidly be developed, incentivised by high demand for potatoes and low supply of labour e.g. potato picking machines (which already exist btw). The sudden increased supply of automation and robotics engineers won't hurt either.
> your supermarket potatoes now cost $50 due to high labor costs
which is as meaningful as $1 potatoes since we don't know the value of a dollar in this hypothetical "everyone is a white collar worker" world. More likely the value applied to all jobs shift, and previously lucrative jobs are not so lucrative anymore; that said, this may not be zero sum, the average standard of living may also increase - but many humans derive their satisfaction relative to the average, a metric that can never satisfy everyone, a poor man in the west today may have better nutrition, health, welfare and SoL than a kind hundreds of years ago.
> people with white collar skills cannot find white collar jobs
This is what I asked - why do you think this is? I'm not convinced.
> there are people w/ master degrees doing Uber
master degrees, in what? If if need to be said: get an education in something useful, and paid well by the market. STEM is usually a good bet.
> they can read and write and do math
But how do those skill translate into something useful for someone else? And how does demand compare to supply?