Yeah that argument is so ridiculous.

You can buy lightly used phones on Swappa for a large discount even when we are talking about flagship phones. There are also situations where someone could be poor but have enough credit to get a phone financed with monthly payments that they can afford.

There are pre paid MVNOs in the US where you can get unlimited talk, text, and on device data, that also includes unlimited hotspot at fairly decent speeds (plus there are ways of bypassing hotspot speed caps, TetherFuseNet is an example open source app) for less than 30$ a month taxes and fees included. For about 30$ a month or so plans exist with QCI priority that are the same priority as premium post paid plans. I have known people who have used their unlimited hotspot as their only internet at home.

Just because some of these people making these types of comments may have a high cell phone bill does not mean everyone else does.

Matrix, it is an open standard and the reference server implementation along with some other server implementationa and the various popular clients are open source. The Element X client and the main fork of it called schildiChat both look a bit like Microsoft Teams. But there are other clients and a company could fork an existing client and customize it to suit their needs or even create a new one if they really wanted to spend the resources.