You would probably have a small flatbed for your business, or rent one from a local, as needed. But it sounds like you have enough need that owning a vehicle would be worth it. I would imagine that, in practice, gaining access to a vehicle would be a business perk, kind of like how a lot of micro businesses will be generous with what they consider to be a business expense for tax purposes. Also, sure, in reality farm equipment would probably be exempt.

Anyway, society is filled with rules and design choices that create winners and losers. Right now, with the current motor vehicle standard, many people gain the convenience of having a car or truck for personal use. But it means we have to spend a lot on roads to carry all the extra traffic, lots of people die in accidents, we're polluting the air, we're dumping rubber into the soil and water (from tires), we're living more sedentary lifestyles, etc. Whenever someone purposes a change to society's rules, it is very common for people to only think of the current positives and the potential negatives, while ignoring the current negatives and potential positives.

Not that this proposal is ever gonna fucking happen.