[Saccharomyces]

The element size was part of the reason that I went with the Anvil Foundry. 

Features:
Switchable Between 120V 1600W and 240V 2800W for Faster Heating & Better Boils.

That is a good compromise between 120VAC and 240VAC operation.  A 2800W unit would require a NEMA 5-30  120V/30A circuit, which is quite rare in the United States.  A NEMA 5-30 circuit requires 10-gauge wire and can provide up to 3600W of power.  One can obtain 4800W on NEMA 6-20 circuit using 12-gauge wire and standard size simplex or duplex sockets.  Not only is 12-gauge wire cheaper than 10-gause wire, a NEMA 5-30R receptacle is more than twice as expensive as a NEMA 6-20R receptacle.

[Saccharomyces]

I don't know that propane is going to become a relic but it's definitely moving out of being at the forefront of brewing. For less than ten gallon batches I can't see brewers opting for the cooler/burner setup when they could buy the increasingly cheaper electric systems. A lot of brewers are regularly brewing smaller than five gallon batches which makes stovetop brewing accessible even on an electric stove. Alternatively, for brewers of those fifteen or twenty gallon batches I think we are a long way off from an electric option at an affordable cost.

As far as electric brewing goes, it started to gain traction with 20-gallon kettle-based setups.  An AIO setup gets to be tricky with larger batches due to the weight of the grain, but if we are talking about traditional 2 or 3 vessel setups, the additional cost to go from 5-gallon batches to 20-gallon batches from a controlled heating source point of view is not huge. The only real differences other that kettles are the element(s) and SSR(s).  The same PID came be used for both setups.