I also saw similar behaviour for Factorio. Right now you have three different versions for download there, via the "Betas" tab. Also when they released the last major update (0.14) they had basically all minor changes as seperate downloads, which they put out in a short time after the major release and I expect a similar behaviour when they release 0.15 in the upcoming weeks. It was around 10 different beta versions.
But on these forums here I've seen it beeing mentioned, that ED have stated they do not release multiple early access versions because it would not be possible with Steam. Maybe it would be a good idea that those people, who claim this to be true, would provide a link to an official ED source with said statement. I assume ED has good reasons for not bringing DCS 2.0.x to Steam but a restriction of the amount of possible early access versions might not be it.
On possible restrictions for DLC during early access by Steam:
I also don't believe that to be true, given that Studio Wildcard could/can sell Scorched Earth as DLC while Ark is still in early access.
Furthermore, I'm not in favor of people trying to advertise the DCS standalone version with "gets updates more frequently" and the like. Those more frequent updates are related to the early access versions for testing, the stable gets the same updates via Steam, just a bit later.
However, using an alpha or beta version of a game means that there are bugs to be expected and the developers want feedback on them. It is meant for people who are willingly playing, possibly broken, games to report the issues to the developer to be fixed. It does not help the developer if people play the test versions because of faster updates, without properly reporting issues.
A better way could be to point out that the standalone version has more sales, in fact every week. If this is a good strategy, I don't know. I guess it is not, given the threads in this forum of people asking for sales of different modules.
But that would be another discussion.