It's because Google is so aggressive, making pressure to enter everywhere, like a parasite. Which is understandable, since spying is their main business, and web browser is one of the main spying apps.
Despite all of their efforts, Chrome still don't know how to handle Bookmarks. Partially because they don't want people to use bookmarks. They want people to click on links that Google offer them at that particular moment. Links that are relevant to Google, not the user. So, if the user finds a great site, which Google don't like anymore, they can simply offer the user another site. Which conforms to current Google's agenda.
On the other hand, Mozilla has problems with finances and developers. They take a very long time to implement even the simplest improvement. But still, Firefox is a less parasitic web browser than Chrome. That's its best feature.
It's like having a very productive co-worker, who is secretly undermining you (Chrome), or having a less productive co-worker, who is loyal to you (Firefox). Of course that productivity means nothing, if he's a backstabber (Chrome). Also, if you use bookmarks, then forget Chrome.