Who defines the value correlation between them, I think that is the question. Plus, there is a difference between time to spend vs efficiencies gained. A future could perhaps exist where autonomous society is a second class to assist operators who also still remain as the interfaces between us - otherwise we are describing large interactive vending machines - how do the machines load and drop off foods, will we have a robotic police society? (thats a new level of fear we haven't covered yet either)
Defines the value correlation?
If you mean "define" as in sets, then you are horribly mistaken about economics. If you mean "define" as in describe, then your question is unimportant.
Nothing has a fixed value, or even a known value. When person A trades thing or service B for thing or service C from person D, the most we can say is that (values) BA<=CA and (values)CD<=BD. It is likely, but not certain, that at least one of the inequalities is actually < instead of <=.
Markets exist to facilitate trades and to gather information on values. By publishing data on bids, offers and trades, markets help people estimate how much other people value things, which helps them decide if they should buy, wait, sell or hold, and what sorts of prices are likely to be reasonable. Money helps too, by suggesting a common scale, though many people have a hard time recognizing that the value of money varies in time and place, and individually.
In the hypothetical world of material abundance, the value of time will be set by the buyers and sellers of time, exactly the same way that time is priced today. How could it ever be different?
