Hmmm, I think you bring up an interesting point Dakota; I guess I hadn't thought of it like that before. I actually think it's a good point.
And Richard, to be fair, Dakota is not trying to cite facts or studies, he is just "wondering out loud", putting forth his thoughts and wondering what others think about them.
I don't personally think Indonesian species necessarily eat 80-90% meat in the wild, but they may well have a higher intake of protein in the form of abundant insects, small mammals (caught or carrion), birds/bird eggs, and maybe even small reptiles.
The problem is that nobody has yet to attach a camera to a BTS to see what they eat in their natural habitat, on the Indonesian or Australian islands ...as far as I know. So we really, to my knowledge, can't say if Tiliqua diet is a whole lot different from that of Scincoides species. But I really think you do have a valid question, and I think you are making a good point.
Like I said, I personally don't think that they are predominately carnivorous. I think if (nearly) ANY BTS had a plate put in front of them that was half meat/protein, half veggies and greens, many would go for the meat, but far from all. But even though food, both flora and fauna, may be abundant in Indonesia, it is, as Richard says, still a matter of finding and catching it. It does still take effort, and there is an inherent risk with walking around looking for food in the middle of the day. BTS are very slow, not very good "hunters". I would guess that the protein they do eat is mostly the stuff that can't run very fast (the slower, non-flying bugs, chicks, eggs, worms/larvae, snails), or stuff that just "happen" to come close enough that a BTS can get a hold of it (in this case I think a hungry BTS would grab anything it can swallow --and if it's too big, might even work at it for a while). But honestly, I do think your logic may be correct to some degree, because the more there is, the bigger the chance that it's going to come walking by your nose.
I don't know how many thousands or millions of years BTS have been living in that area with abundant flora and fauna. My "hypothesis" would be that if they truly were that carnivorous "at heart", they would've evolved more carnivorous traits. I think we would be seeing some forms of Tiliqua with much more evolved teeth, and much more leg-strength, and so forth. In my uneducated thinking, if it was that available to them, and that beneficial for them, nature would show it. But so far nature is showing us Tiliquas and Scincoides living in very different habitats, and under very different conditions, but still looking, acting, functioning, and eating
very similarly.
I don't think you can necessarily compare abundant food sources with what an animal goes for on a plate placed in front of them. I do think you are making a good point, and asking a good question, but I think what Richard is saying, and I agree, is that it may not be as simple as it seems when looking at the habits and preferences of our captive skinks.
We try to mimic as much as we can of their natural habitat to keep our skinks happy and healthy, but the way it is in nature is not always the most beneficial for our animals.
If someone out there has experimented and has experience with a higher protein diet for their skinks, I hope that they will speak up.
Dakota, am I correct in assuming that you are thinking of maybe feeding your skinks a much higher protein diet?
I know that you are very concerned with doing what's best, and what's most natural, for your skinks, and I know you are wondering if something, other than what's been done for years, might be BETTER for them. But keep in mind that ANY time you experiment with live beings, you are taking a huge risk. You are quite possibly risking that animal's quality of life, maybe even its life. I think that the people who have very strong feelings for not deviating too much from what's been proven to, not only work but, be optimal for our animals, are probably the ones who feel that this experiment is not worth risking.
So I really hope you will get some responses from people who may already have tried what you may be pondering. And that they can tell you what their findings are, good or bad. I hope people will pipe up with their thoughts on your question, whether they are agreeing with your thinking or not.
But I really don't think there's any need to be jumping down Dakota's throat for posing his thoughts and question. I think those of us who choose to contribute our thoughts, opinions, and/or knowledge, can do so in a non-ridiculing manner. Not trying to back-seat moderate, just a suggestion.

Breeder and keeper of Meraukes from 2010 to 2022.