Phone calls are actually great, especially in these days: it's the only way to ensure you can have a stable, consistent conversation with someone that's not standing in front of you (individual or business), in an age where it became socially acceptable to skim text messages without reading them properly, leading to obnoxious, error prone communication, or to just stop replying to people whenever you feel like it, even when in the middle of a somewhat synchronous messaging session, in particular when you're forced to make a decision or relay bad news to the other party (the horror!).
"No one should ever be able to interrupt me, absolutely ever" is a disturbingly entitled and modern take. Not too long ago, it was perfectly fine for people to turn up at your house unannounced, to pay you a visit, for no reason in particular other than to engage socially and you were expected to host them at your house (!). Surely we can deal with the very occasional call from someone that wants 5 minutes of your time, no? This opinion is so popular that I wonder if I'm the only one who doesn't have dozens of people competing for my attention on a daily basis.
If spam calls are an issue (and I understand they're absolutely horrid in the US, whereas in the UK, where the author is from, you may get one or two spam calls ever couple of months, from my experience), just don't answer unknown numbers unless you're waiting for a specific callback, as most people do.
The article then goes on about a couple of unrelated things that have nothing to do with telephones, such as companies having inadequate customer support channels or online banking functionalities. Taking his Barclays example, he could do what he wanted (adjust loan repayments) in branch, yet it is of course time consuming to do so. If Barclays was unable to service him by phone, would he also be denouncing "talking to people in real life" in general because that's the only method this particular bank offered him for servicing his account? No one is arguing changing your loan repayments shouldn't be an online banking functionality there.
And yes, if you're ill but can't be arsed to call your NHS GP, then you're clearly not sick and shouldn't be tying up already strained public resources. If you do have a proper disability, then I do believe your GP should arrange for an alternate means of communication with you. "I don't like phones" is not a disability, it's entitlement.