It's the most basic situation when you need to add a button to the web page, and it literally takes several hours simply because you need two specialists for this process.
CMS have a monolithic architecture with lots of features, most of which are simply unnecessary, and, what's more, cannot be disabled.
Most CMS are written in PHP. Only experienced developers are familiar with it. As a rule, they are quite expensive and hard to find. On the other hand, there are lots of young and promising (and less costly) specialists who prefer more "fashionable" programming languages.
Many outdated features
High cost of maintennace
Tightly coupled backend and frontend
One major advantage of Saleor is that it is a perfect alternative to the existing heavy CMS for projects that are constantly updated and have a complex IT infrastructure.