Simply put a spike in blood sugar due to a sugary food is much, much bigger than the drop in blood sugar sufficient to trigger a change in eating habits. And that's before we consider the impact of non-insulin hormones on our behavior, such as Ghrelin, which won't show up on a blood glucose test at all.
https://www.healthline.com/nutrition/artificial-sweeteners-b...
[1] e.g., https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6363527/
> So far, only saccharin and sucralose (NNSs) and stevia (NS) change the composition of the gut microbiota.
[1] https://journals.plos.org/plosone/article?id=10.1371/journal... [2] https://www.mdpi.com/1422-0067/22/18/9863
Is stevia ever used alone? If it's just a "fig leaf" so to speak, then perhaps the health effects of the sugar alcohols would be more relevant.