I feel like you're viewing this as a zero-sum game though (which it isn't)
If you're not competitive enough as a premed, then you can always transition to pre-dental, if still not competitive, then you can do PA school, if still no good then you can go for podiatry, and then there's always optometry, physical therapy, nursing, dosimetry etc. etc.
There are plenty of options you can take with a biology degree with premed coursework complete, most of which offer a 6 figure salary while having the opportunity to take care of patients (while having less strenuous/stressful training).
In fact, I'd argue that a biology degree is even more stable than something like a computer science degree. If you go into computer science and find it just doesn't click for you, there isn't anything you can fall back on considering the only route you have is a coding-oriented profession. While with biology (w/ premed courses), you have plenty of fulfilling, high-income, recession-proof occupations you can go into.