> If the first thing thousands of users do after installing WordPress is to pay for a page builder plugin to be able to work with their content in the way they want, that's a problem
Or, it's an opportunity. Look at Shopify - is it a problem that the first thing a new Shopify user does is to head to the Shopify app store to buy and install a handful of plugins?
Completely agree that access to plugins is a huge plus. Except if a very large number of Shopify users start to install the same plugin or plugin type, and you start to see articles titled "60 of the best [page builder|digital download] plugins for [WordPress|Shopify]", and you field daily support requests asking, "which page builder plugin should I use?", and users actively avoid an existing feature in your service to use a third-party add-on that does the same thing your feature was doing only better. At that point it's a great candidate for a core product feature or enhancement, as has been the case with Gutenberg.
Also worth noting there is no official WordPress.org paid plugin store and paid plugins are typically not hosted services as with Shopify.
The average experience WordPress users get when shopping for, maintaining, and getting support for plugins is much less smooth than a hosted platform like Shopify. (There are great WP plugin developers and terrible Shopify ones too, but fewer of the former than the latter.)
Or, it's an opportunity. Look at Shopify - is it a problem that the first thing a new Shopify user does is to head to the Shopify app store to buy and install a handful of plugins?