I worked on WordPress for about 7 years before switching over to Squarespace for my clients. I haven’t regretted the move in the least. I enjoyed WordPress and I appreciate how powerful it is, but for the very reasons you shared in your article, Squarespace has been a much better fit for the majority of my clients.
I resisted Squarespace and similar WYSIWIG web builders for several years. I didn’t see them as “serious” platforms for anyone who wanted a “serious” business. It took a number of years for Squarespace to come into its own, and there are still problems/room for improvement — as they’re always will be with any kind of software. But I can attest that it is a powerful alternative for those who do not wish to go the WordPress route, which like you, I’m finding more and people who don’t.
I don’t see WordPress going away any time soon and it would be many, many years before it could ever get phased out of the interwebs. So I would like to see WordPress adopt a more simplified CMS structure, and I hope that attempts like Gutenberg will improve WordPress’ usability and appeal.