Every single study I have seen refutes your point, which was commonly brought up during the Obamacare discussion days and never had any merit to begin with. Here's the NIH itself estimating a 13% savings compared to today:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8572548/What you're missing is that the current "system" is so utterly wasteful and inefficient that even if we cover people's shitty lifestyle habits it would still be cheaper than what we have today. Which is basically what TFA's main point is about.