Having said that, I think a key phrase you used is "at the moment." I definitely don't think it's outside the realm of possibility that we'll eventually reach the point where we don't have to test on any living subject. With how far science has come in the last few centuries alone, I don't really think you can rule that out.
However, let's say you're right (which you definitely could be) and that we never reach the point where can safely produce essential products without some form of animal testing. I think that a world where we use animals for only that purpose is a lot better than the world we live in right now. We'd still see a literal world of difference if we stopped using animals in every other way but this way.
I've heard of select cases where people for some reason or another need to consume animal products. I think the amount of people who do is greatly overstated, but I acknowledge that these people exist.
As I've said, though, most people can be perfectly healthy eating a 100% plant-based diet, but they choose not to because of convenience or personal pleasure reasons. For these people, they're not exactly justified in eating meat. I'd argue that even those who supposedly can't be vegan should be making a genuine effort to minimize their animal product consumption.