I think a big part of the issue is that as the popularity of synths and electronic music has grown, the costs inflated to the point where people began to call for cheaper products more and more.
People trying to maximise on ‘classics’ and ‘vintage’ synth prices also played part in the these desires I think. So many people know these machines but haven’t ever used them as they can’t find one, or afford one. Take the status given to the 808 and 909 as an example. Same can be said for all the people who have owned machines like this, but can’t keep up with the ever growing second hand prices.
Behringer seem to have stepped in to take advantage of that gap in the market. They could potentially destabilise the second hand market also, as the number of people prepared to pay extortionate prices for a 808, 909, or whatever shrinks.
As far as ethics go, I don’t imagine Behringer are concerned, as they are simply taking advantage of an opportunity to secure profit.
As crazy as it sounds though, I still think that if roland released an official 1:1 reissue of any of their classic machines, and managed to keep the price reasonably affordable, it would weaken Behringers efforts in regards to the 808 and 909. I highly doubt they will though, Japanese companies are very complex, bureaucratic and unlikely to act like Behringer does in my experience.