I'm not saying the cost is significant in the grand scheme of things, but unless you own the whole physical network, the co-lo facility and the IX then your transport, crossconnects and port costs are OPEX, not CAPEX.

Transport, crossconnects and port costs apply regardless if you use a public IX or do private interconnects.

Here's a link to the study about settlement free peering: https://www.pch.net/resources/Papers/peering-survey/PCH-Peer...

I had the percentage wrong, or then I may recall a more recent study. This one is from 2011. Of course it depends greatly upon who you peer with, as to whether a written contract is needed or not. As such the sampling may skew the results.