This is only possible if the number of available estates was kept close to the number of active players at any time, or at least those who in some way have expressed interest to own one. Like, if they would release a new batch as soon as increasing demand is detected. And would commit to doing so indefinitely. Everything else creates scarcity, which creates the market conditions we have.
Of course, this is by design, so one would need to convince them to change their mind about it. A possible rationale might be that it would create an income stream for them which is directly proportional to the increase in participants (they don't benefit from aftermarket trades). There may have been reasons in the past why this was just not happening, but with the new engine there should be hope to turn the trend around. Then there is only the issue of this having been condoned for so long that many take the status-quo for granted, and there would be significant adversity from existing estate holders.
As a sidenote since we're about shops specifically, I am thinking the same about shopkeepers. The way their market price has developed makes them an interesting object for speculation in itself, rather than just a tool for running a business. I think they should be craftable without any choke points in their supply chain, and should have never been made rare at all.