This is the collective genius of everyone driving around looking at their phones. The government realizes that worrying about vehicles’ mechanical state is like rearranging deck chairs on the Titanic.
I mean, we’re a big country, we can do both. There’s also a strong correlation between people who are unsafe in one dimension making bad choices in others so things which are easy to enforce would be useful for re-establishing the idea that use of public roads is governed by laws.
It's not for the government to save money, it's to make transportation affordable for poor people. Some of the states that require inspections do it for almost free, because they delegate the task to private mechanics to do, and they charge for it.
It’s been explicitly billed as a cost savings in a few places I’ve lived (nothing is easier for a politician than bashing the DMV without mentioning that the parts voters don’t like are ensured by your legislative decisions) but if access to the poor is essential, driving is already so heavily subsidized that we could have some kind of assistance program. Most of the people benefiting from lax enforcement are not poor - those luxury trucks and tricked out cars are a middle-class hobby - and the resulting injuries aren’t free to treat.
Ehh, I feel like if I go to a poor neighborhood and I see a lot more minor inspection issues than I see lifted trucks in suburban areas. Rust perforation, bulbs out, bald tires, worn bushings, bad shocks, missing panels, etc.
The vast majority of states don't even have safety inspections, and some have recently discontinued them.