The fallacy everyone is making here is believing that consistency trumps all else. But it doesn't if you're consistently subjecting yourself to a stress which does not result in any new adaptations--then there will be no change.
An oft repeated example of this fallacy is in the case of tanning. If you go out into the sun for 20 minutes and get a tan, what will happen if you continue to go out in the sun for 20 minutes each day? Will you get more tan? No. You've already adapted to the stress (ultraviolet light exposure for 20 minutes) and so the continued daily stress of 20 minutes of sunlight will not result in any new adaptations.
That is why if you are completely untrained, sure, VR constitutes a sufficient disruption to homeostasis that you'll get some muscular adaptations. But the stress is so minimal (and you cannot effectively increase it) that you will quickly adapt to it and subsequent exposure to the stress in the future will not result in any adaptations, it will only maintain what little adaptation you already have.
"Consistency" in this instance probably means exercising more than once a month. I think you're comparing VR exercise with a hypothetical ideal based on your own exercise routine, when it should really be compared with what a given individual was doing beforehand, which is probably some kind of cardio with no upper-body impact, or absolutely nothing.
An oft repeated example of this fallacy is in the case of tanning. If you go out into the sun for 20 minutes and get a tan, what will happen if you continue to go out in the sun for 20 minutes each day? Will you get more tan? No. You've already adapted to the stress (ultraviolet light exposure for 20 minutes) and so the continued daily stress of 20 minutes of sunlight will not result in any new adaptations.
That is why if you are completely untrained, sure, VR constitutes a sufficient disruption to homeostasis that you'll get some muscular adaptations. But the stress is so minimal (and you cannot effectively increase it) that you will quickly adapt to it and subsequent exposure to the stress in the future will not result in any adaptations, it will only maintain what little adaptation you already have.