Imo it's not as big of a deal as people make it out to be and I truly doubt in the end it will have much of anything to do with when VS is "finished"
It's a separate small team working on what is essentially a officially sanctioned mod.
and because it's a separate team It is unlikely to slow down progress on VS by any significant amount.
Ironically, I think the new gamemode would be far easier to add because it's core mechanics are likely to be much simpler than VS
and let's be real VS as a hardcore uncompromising survival is a niche compared to the potential of "Minecraft but good" and if this gamemode did well for them it could bring a ton of new players/funds so should they decide to hire more people the still could.
Something I don't think most people understand is the sheer amount of systems and mechanics VS has is what makes it take longer than something simpler like Minecraft or Terraria.
There are so many more considerations to make down to silly things like putting tool molds on shelves lol
and this isn't directed at you but in general I've seen people complain about the pace of updates which I find kinda odd,
Since I've been paying attention they seem to update the game at a fairly decent pace and they're usually pretty big updates considering all the features added and bugs fixed.