Eh, it doesn't work like this unfortunately; pay is never a mirror of the dangerousness, the utility, or the dirtiness of the job. I would say that usually it's the contrary: the more essential a job is, the less it is paid.
No, pay corresponds with the skillset and how replaceable you are (moreso how replaceable). Walmart truck drivers are highly compensated because trucking is a lonely and relatively uninteresting job to do. Doing that for many hours requires a certain type of person and would mentally wear down most people.
Walmart requires a consistent level of output which they hope can be maintained by keeping truck drivers happy with high pay. Other trucking companies can afford to have some drivers leaves and thus pay them less because they have some leniency for delays which Walmart cannot/will not tolerate
