This sounds like an optimistic comment from a decade ago. Cost of storage has gone up recently, as a glance at data-hoarder fora will show. Phones have less storage capacity nowadays inasmuch as many manufacturers are removing SD card slots. The idea is that normies keep stuff in the cloud; self-storage of very large amounts of data is an edge case.

In my country, the typical laptop purcase from a retail chain is still 512GB or so, and moreover, few and fewer people own a laptop since it is becoming normal for a smartphone to be one's only computing device outside the workplace (even uni students are foregoing "real computers" now). Anything more than such a basic laptop is a premium product, and premium products cost premium prices.

Offline-first used to be the norm before everything started requiring an internet connection for some reason. I was using OSM data offline 15 years ago on smartphones.

The reason it moved to the internet was not that it wasn't possible to stay offline-first. If the app depends on your server, then the owner can monetise that (e.g. with subscriptions) or track the users. It is more interesting for companies than allowing the users to buy a snapshot of the maps once and never come back.

Offline-first nowadays comes from open source projects, not from companies.