Earlier quoted context omitted.
I'd like you to expand on reasons for this? I can think of a few for some cases.. However I have around 50 websites or so that are running just fine without Gutenberg.. and if you count the number of updates WP and plugins and themes have rolled out since Gutenberg and multiple that by 50, most of these updates have been an annoying use of time. That being said, Gutenberg stuff today is pretty mature and I do recomme…
As you said Gutenberg (and now FSE) are in core and the default for developing and authoring WordPress sites. For ClassicPress to be an alternative, you would've had to have intentionally veered from what WordPress gave you. Sure, some sites may have chosen to use a site builder or Classic Editor with ACF, but those that didn't are left out in the cold by ClassicPress's decisions.
I don't think it's just 'some sites' choosing to use other builders and reject Gutenberg. the plugin repo shows that the 'classic editor' plugin has over 10 million active installations.
(classic editor removes gutenberg from the backend screens) - so it's not being left out in the cold, it's keeping things running fine without Gutenbloat.
So there was/is a huge need for ClassicPress - it's just that there is an easier way to get a very similar result with WordPress and that is install an extra plugin to remove the 'new plugin' of Gutengerg -
and since it's so easy to get back the functionality with a few clicks, may people are leaving many websites without the performance boost of leaner WP and getting the same classic backend..
If autaomattic had not put the classic editor in the repo, many more would of sought out the fork and classicPress would be dealing with more than 10 million sites relying on it.
This has been a pretty big issue for some time now, and only very recently would I start to lean into Gutenberg being a mature enough replacement that I start to advocate for it's use.
But really there is no need for it - if you wanted a page builder years ago there were plenty, and still are.
The great thing about it has been the pulling in other aspects like performance issues and reusable styles and such - so it has helped make WP better in other areas along the way, so now I am okay with it.
Being left out in the cold without Guten just means a leaner site that loads faster unless you get into elementor or some other heavy bloatware to have click/drag GUI - but it's not the only option now or back then.
Today, it's fine either way.