Nothing you say is real
No need of paid tools, there's a ton of tools, you can add cache without cost, add Redis connection with just a click and so on. Only the Anti Spam, Akismet, is semi-paid (provided by Wordpress unless you have ads on your site), and you can put whaterver you want on it, you are not forced to use anything extra.
It's relatively easy to mantain (if you know a little) and the refactoring thing doesn't happen often.
Its versatile, you can use it or develop from zero your own CMS, but clients need a speedy option and they pay for it, so the huge ecosystem it has is really good for bussiness, and the openess it's a plus, you can develop whatever you want over it and keep it working, it's just PHP and MySQL, pretty easy.