Their solution appears to be actually worse than the initial state, if they simply automatically split the long pages and add "prev - next" buttons.

The proper solution for them is to look at Wikipedia as an example. Tables of contents in longer articles, manually introducing the new topics or reorganizing when it's reasonable. And it's not something that can be automated.

Automatic splitting of long pages to shorter ones is good only for "we get money for clicks" media but not for a repository of knowledge with serious intentions.