Yes and no. They don't use the kind of co-location services you might be thinking about.
Co-location targets the corporate world. Corporate world loves it to just hand off the servers and have it run for them.
But if you go to a company such as Interxion/Digital Realities, they will just send you away (or more specifically, send you to one of their tenants that offers co-location services), because they are primarily real estate companies.
They rent out empty rooms designed to be used for servers and even office space on their campuses. These are normal lease agreements and their purpose is that you put your own staff and infrastructure there. And that's what most mid-sized to large cloud providers actually use.
They wouldn't even have the employees to touch servers or network equipment. What they take care of is ensuring that the AC is working, that the shared Diesel aggregates are ready in case of a power outage and that there is security personal patrolling the campus, but they won't enter rooms rented out to customers just like you wouldn't expect your landlord to go into your flat.
(Equinix is a bit special on that point, since they offer both. You can get co-location too through Equinix, but it's probably not what AWS, GCP or Azure is using.)
Owning real estate simply isn‘t their main business purpose and has many downsides, especially in matters of scalability. The main pro reason for owning them is cost. Owning the buildings makes you less flexible but saves you money in the long-term.
One more point in favor of leasing is: the relevant „neighbors“ are just next door. If you own the real estate, it‘s probably in the middle of nowhere, network-wise, and you end up spending lots on laying fibre. Whereas with leased space, other providers are likely on the same campus and all you need is a few 100 meter or one km of fibre to reach the next building or even just the next room. If you are small enough, these savings on connectivity can even end up making it cheaper to lease.
Might be a surprise to many, but it‘s primarily the budget providers (Hetzner and OVH) that own their own buildings.
Most others just have long-term leases with whoever owns the real estate (usually Equinix or Interxion/Digital Realities, as they more or less own most big DCs around the globe).
Also, I guess many miss-understand what „not own the DC“ really means. These services aren‘t the kind of retail-style colocation offers. Those providers rent entire rooms or even buildings there, run their own infrastructure in them and frequently have their own staff and offices on site too. These lease agreements behave more like a usual office or warehouse lease, not what some here might think.
Lucky you, somebody already did that for you. It‘s called DNS. :P
On a more serious node: IPv6 can be short and if used right they are actually short. Unfortunately, people continue not to care about relearning their habits and treat IPv6 as if it‘s a 1:1 replacement of IPv4 (you can even see it in this threat when people ask „why would you need more than a /64“). A major blocker in IPv6 aren‘t just the IPs but that all sys admins out there are trained to treat IPs as they got used to from the v4 world and can‘t stop to think of them as scarce resources instead of applying a hierarchical approach.
Co-location targets the corporate world. Corporate world loves it to just hand off the servers and have it run for them.
But if you go to a company such as Interxion/Digital Realities, they will just send you away (or more specifically, send you to one of their tenants that offers co-location services), because they are primarily real estate companies.
They rent out empty rooms designed to be used for servers and even office space on their campuses. These are normal lease agreements and their purpose is that you put your own staff and infrastructure there. And that's what most mid-sized to large cloud providers actually use.
They wouldn't even have the employees to touch servers or network equipment. What they take care of is ensuring that the AC is working, that the shared Diesel aggregates are ready in case of a power outage and that there is security personal patrolling the campus, but they won't enter rooms rented out to customers just like you wouldn't expect your landlord to go into your flat.
(Equinix is a bit special on that point, since they offer both. You can get co-location too through Equinix, but it's probably not what AWS, GCP or Azure is using.)