Let's assume that the company has more cash that it can spend now, that its free cash flow grows faster than capex + opex. Then, if an equity raise is "incredibly cheap for shareholders", that would mean shareholders consider the stock price to be higher than what they expect in the future, i.e many would be selling and the stock price would come down. I don't assume the stock market to be rational but this thesis does not hold much, as the company can easily raise debt now, at a much cheaper price for shareholders than equity. Let's wait and see.
They can easily raise debt, but it will still be a liability on their balance sheet and they will have to pay it back.
What if the stock price falls by the time they have to re-pay the loan? What if free cash flow dries up (as most of it comes from selling credits, not cars)?
You’re assumptions paper over the risks/liability of debt while also assuming the stock price stays at today’s level (or keeps rising).