> Of course, there’s also the simple thing of “enterprise stuff costs more for no reason.”
That "no reason" is usually a combination of the following:
1) Support avenues - commercial customers want rapid support in case something breaks, including overnight / on-site repair. That infrastructure costs more money compared to consumer appliances where the customers have to ship stuff to a central repair place.
2) Quality. Consumers are used to stuff failing after 3 years and get the next new hot thing, commercial customers want a decade or more in life span with as few maintenance calls as possible - and especially they don't want to redesign enclosures when the model is no longer available so they demand longer shipping times - again, on the order of 10 years or more. Also, these displays generally have to work in a wide variety of environments - directly in sunlight/heat/cold, vibrating/otherwise moving. Higher quality components cost a lot more money. Add more money for certifications required for medical or military deployments.
3) Spare parts. Again, the longer availability terms mean more costs for the support infrastructure - while for ordinary TVs the parts stock can be emptied out after 3-5 years, stock has to be kept around for way longer for commercial TVs, and that includes buying up spare parts when a supplier EOLs a part.
4) Features. Commercial TVs tend to have more selection of (rare) inputs, e.g. BNC or SDI (the latter to drive an array of screens around a spread-out location from a single signal source, you can't do that with HDMI).
5) Firmware. After three to four years no manufacturer except Apple gives a flying f..k about the firmware, which means security holes go unpatched. Commercial customers demand longer update cycles (and better validated ones), again that costs more money.
6) Vandalism and elements protection. This one is huge and ties into the quality part. While your home TV won't need to be protected much against anything, vandals will go and attack anything without mercy - with anything from graffiti over hammer blows to hydrofluoric acid. Add to that nature: bird crap, vomit, tree sap, pollen, drunkards stumbling into your digital signage... or humidity/harsh rain.
7) Loss of revenue from advertising, as you mentioned.