They haven't done the maths, but I suspect that each ad served over mobile data earns the mobile carrier far more than the advert earns for the page that hosts it.
Mobile carriers should be banned from charging for data involved in serving ads .. and given the option of blocking them instead.
If Ads were much lighter and better behaved, I there would be such a problem with advertising - Both for the publishers and the consumers.
On desktop chrome, my default profile runs uBlock origin and blocks all third party js & frames. Much faster, & you can selectively allow 3rd party content.
Edit: your solution is much less technically complex, and less intrusive than carriers inspecting traffic for billing purposes though
Not that this would be popular, as people would just click "no" on the "pay 1c to read this page" dialog.
Three, the UK Carrier mentioned in the article has unlimited* data plans, every extra bit sent over their network costs them more, that why they're looking into ad blocking.
* Subject to rate limits for "aggressive" use.