Note that it's hard to quantify this evenly between ISPs, because isp A might have a hundred gig port to an ix and meet all the major cdns and Netflix and Google (YouTube video traffic) over the ix exclusively, while ISP B might have also a hundred gig port but also set up many PNIs for direct cross connect and peering with the largest cdns and sources of traffic.
Meaning that ISP B will need to upgrade its ix port at a much later date relative to subscriber count, but its PNIs and cross connects are opaque and hard to know about from a public/external third party perspective.
Meaning that ISP B will need to upgrade its ix port at a much later date relative to subscriber count, but its PNIs and cross connects are opaque and hard to know about from a public/external third party perspective.