How many veterinarians got into the game to become relentless, driven, scrappy and indomitable business owners vs because they love furry things and helping?
Depends entirely on fixed vs variable costs. Rollups (which are very common now) work mainly because most "mom and pop" businesses can easily be "unlocked" by pooling the treasury, HR, accounting, commercial banking, supplier negotiations etc.
Assuming you had $$$ for some supplies but couldn't afford to lease a commercial building, you could provide small mammal services from your vehicle, driving to people's homes to give vaccinations and well care.
Being mobile would also allow you to serve a larger market than a fixed clinic; you could serve a couple small towns on Monday, a couple others on Tuesday, and server a larger metro on the weekends.
Once you're consistently profiting $$$$/day you'll be able to start saving for the equipment you'll need for a commercial lease somewhere because you have both the cash, cash flow, a loyal customer base, and critically, a good sense of where a good location would be to serve them from.
Even if they are lucky enough to have no debt, I don't think the average graduate has $10,000+ in the bank to spend. I have never started a business so I honestly have no idea how hard it is to get a small business loan for something like this, maybe it's easy, but even so it's certainly risky.
Except every newly-graduated veterinarian does have a massive loan on their books, in the form of student loans. And even if she didn't, where does the startup capital for her clinic come from? Whether in human or animal medicine, starting your own practice--especially as a new grad--is usually the course of action with the highest-risk-to-lowest-pay ratio.
If it becomes too much, things actually happen.
(This is the dark side of financialization, as it can be used to maximize human misery.)