Given that mmWave radios need clear line-of-sight to work properly, many 5G radios are going to end up being installed on poles. Somehow I doubt a building owner is going to match the $48 per year cost for me to rent a pole from an LDC, or $12.96 per pole per year from the incumbent.
https://www.verizonwireless.com/business/real-estate-inquiri...
I expect you'll find more info further down the page.
1. What are they actually leasing? Are you leasing them land, or a pole, or the right to install equipment on a pole?
If it's either of the latter of the two, what is the wind and weight loading capacity of the pole? Who certified that? When was it last inspected? Who owns it and what are the maintenance obligations on it, so the part closest to the ground isn't corroded through by passing dogs using it as a toilet.
This matters to a Telco installing equipment, as they don't want it to fall on someone (or for their equipment to be too heavy and damage your lighting pole, and you to have a claim against them). You also don't want to have them claiming against you for the replacement of a macro cell mmW base station with an active antenna system if the lamp post falls over, as their kit is expensive.
2. What power is available? Is it independently metered, or an unmetered street lighting circuit? In some countries, you want a metered supply unless their radio equipment and similar is pre-rated by the energy company. Given cell sites use variable amounts of power, they likely don't want a fixed charge based on rated capacity. If your carrier installs backup power, is there space?
3. What network is the fibre connected to? For most mobile operators, they don't want a standard domestic GPON broadband connection - they'll usually want fibre connectivity to one of their transit network providers. What's the redundancy and fibre route like? The provider probably doesn't want to add another fibre provider to their supplier setup, unless they'll be adding lots of cell sites on their network. Usually operators don't like sitting adjacent to end users on a fibre network either - they prefer to sit in their own isolated network. Can that be delivered? Who's responsible for this?
4. Is there enough space for a communications cabinet at the base of the mast? These can be quite large and put out quite large quantities of heat. Is it opposite a road intersection that means it is more likely to be hit if someone blows through the intersection?
5. How long a lease are you offering? What's their certainty of tenure? They won't want to go to all this effort if they aren't getting long term confidence. Dealing with a single site owner can be annoying, as it doesn't scale.
6. Are there enough users to create a business case for this site? A European carrier needed an approx 1.5m EUR business case for return on investment over 3 years before it would even consider building a cell site, outside of their planned build - adding something new into the cell grid doesn't always make sense.
Site/tower companies provide aggregation to carriers and their supply chain partners (a lot of this varies in different markets), but on the whole, while in theory a lot of this is easy, it's actually far harder to provide an offering that "fits" the operator supply chain expectations. With mmWave, more sites are needed, so some of this will need to become more flexible, but on the whole, carriers are quite traditional in their ways.