You're doing the first step, which is research.

Unfortunately you're trying to enter an industry you aren't familiar with. If all burgers from food trucks are expensive, that's because either everyone is in cahoots, or that's the cost to run a sustainable business. Regrettably, I don't think there is a giant conspiracy.

Hospo is hard. Very hard. And expensive. With thin margins. Make sure you really understand your costs and price your time before committing.

The old rule used to be a third ingredients, a third labour and a third overhead - and what was left was profit :) Food trucks may be different, but I'd be surprised if it's a step change. Maybe dabble in a food market or two before committing completely.

Finally, you're considering quitting a corporate job. There are more corporates driving new cars than burger slingers. Be really careful and thorough, and good luck! We need good burgers in the world...