According to devs (see LCV4.0: difficulty raised? - #4 by Gewehrztraminer_1664 ), it is not really possible to target budget category so early, they’ll likely be only buying used cars.
Budget demographics, especially at the start of the campaign are NOT supposed to be catered to, because that is, as you have found out, impossible while turning a profit, so don’t.
They are second hand buyers.
I thought I had the same experience in the past on Archana (success by targetting budget) but that’s different now.
Not to mention that probably the game is right in the sense that there was time was owning a car was not an obvious thing, that the ability to buy a new car meant being higher than budget category?