The question is how much and how many will pay for a better unit.
For example, if Flex dropped the forced rotation feature from the DA, I doubt the price will not drop much. The cost to engineer (design, tool, etc) a new machine is not cheap so unless there was a ready market (detailing market is probably not that big in the grand scheme). It seems like the current machines are all fairly similar and mostly coming out of China so in the end they would need to invest the time. So, would the market pay say $250 for a better non-forced DA? Sure, they will sell plenty but given how cheap some buyers are, the other units will continue to sell.