I dunno, seems like the freeloaders vs. the arrogant, depending on point of view. Both sides can sling barbs at the other.

As a practical matter, though, I think there's a reluctance among airlines to directly and too transparently link benefits like upgrades directly to revenue. Certainly they may value the people who pay Y fares or close to Y a lot more, but they're also mindful that companies generally don't like and are suspicious of the programs, seeing them as a form of kickback that might influence employee behavior that runs counter to the best financial interests of the company. If the airlines made it easier you'd see a lot more attempts at reclaim programs or negotiating special categories of fares that don't earn miles. The thinking is that the programs add costs that companies pay in fares while generally getting no benefit (to the company, as opposed to the employee) in return.

If benefits are too obviously tied to dollars then I think it would lead to even more oversight, as well as (often well-founded) suspicion that employees might be gaming the system by booking business travel unnecessarily close to the last minute. Travel costs are almost always one of the first things companies try to cut when budgets get tight. Countermeasures are often very blunt instruments (i.e. one-size-fits-all directives, like "thou shalt drive if the destination is 250 miles or less or you need (honcho level) approval." But companies taking countermeasures is generally not a good thing for airlines, so it's best to make benefits and the granting therof as opaque as possible. Not unlike fare pricing.