Way way way too early to say we need to ditch firefox.
What we know is that Mozilla, firefox's parent, bought an ad company with the stated goal to make privacy friendly advertisements.
Also this week (I believe, maybe a bit earlier) Firefox announced that they are holding to manifest v2's rules for adblocking, that they are encouraging ublock and other apps to still block ads.
Firefox needs money to continue development though to be competitive with Chrome. Ads are the only real way to make money on the internet. There is nothing that suggests that they are adding ads to firefox, to me it sounds more like they want sites to use their privacy focused ad service to fund their development of firefox because they weren't receiving enough donations - which makes sense.
I'm not going to ditch my browser of 20 years over fear that something might happen. If something happens like that, then sure I'll change to something else. Remember though, all of the alternatives are chromium based, which is mostly controlled by Google. By giving up Firefox you're allowing Google to make their monopoly, because Firefox is the only other real browser engine out there.
So, rather than be reactionary, I'd say let's give them the benefit of the doubt and see where it goes.