If you haven't used Chrome, no wonder you haven't noticed Firefox sucking. But a side-to-side speed and responsiveness comparison of Chrome and Firefox is unfair even today.
Firefox doesn't suck, and matches Chrome. But there's no accounting for user behavior. I have seen user behavior that is mind-blowingly stupid, and subcultures of user activity and tendencies trace well with product loyalty trends.
Some user subcultures are retardedly dependent on browser extensions, never clear their cache, retain cookies for the lifetime of their laptop battery, and seemingly need hundreds of tabs open. And none of this shit makes sense to me.
These are likely the same people who carry around phones on the brink of overheating while locked, and in their pocket, because they have to have a thousand apps installed, in order to feel like they're getting the $1,000 phone they paid for, I guess. Their emails are constantly peppered with "sent from [app|device|service]" signatures, and they claim microphone permissions are why ads target them.
Honestly, if you've been blaming the browser, it's more likely that you're the one being your own worst enemy.
And, yeah, if Mozzila likes dropping numbers, nothing has to change.
Just this last month I've had Firefox crash tabs daily that Chrome handled perfectly fine, I've seen it crash the entire browser when Chrome did just fine. Underlying both those issues was a janky Windows install that was partially broken. But still, Chrome carried on like a trooper.
I've even just switched back to Linux and immediately saw Firefox stumble over scrolling frame rates. That was caused by using an Nvidia graphics card and the proprietary drivers on Kubuntu which was a bit janky again to say the least. But Chrome carried on through again with no problem.
Just today I've switch to an AMD graphics card and the opensource drivers on Fedora and only now is Firefox seemingly playing nice.
It's a great browser (though Dev Tools don't seem as good to me) and I love the containers but it does seem it needs a bit more of a particular environment to operate just right whereas Chrome 'just works' more of the time. That is possibly why lots of people say 'fine for me' (it is for me now, yey!) but others say "it's broken" or 'slow' or whatever.
( And as a user I knew that too. I just wanted to support Firefox. )
So saying Firefox Doesn't suck may be partially right. As we will have to define "suck" first. But saying it is as fast as Chrome during Firefox 4 and early Chrome era is just the same as saying earth is flat.
Google's own websites are some of the major culprits. The funny thing is that similar webs don't have this issue, and I don't notice any slowdowns that push me to do side-by-side tests.
Chrome feels like an untamed animal which does stuff without telling you, and I don't like it.