That's not the first thing that comes to mind when you mention "monetisation" these days to the average gamer or gamedev. Without further context, the word is usually interpreted as bleeding your customer for more attention/money.

And this is the model that's being criticised as archaic and stupid here.

It's really not. Just making a guess is what he's talking about. You still need to right price a full paid game and I'm sure Unity would be happy to help you figure that out.

What does a game engine have to do with pricing? He is clearly talking about how Unity will soon let you introduce in-game ads/payments.

You can already introduce in-game ads and payments with or without Unity's help. I understood the article as describing some sort of auto-detection feature that suggests where money-making hooks can be introduced - sort of how Youtube supposedly suggests to content-makers where would be a good spot to insert an ad break in the video.