I believe Swedish/Finnish membership has been officially accepted by NATO. All that remains is collecting the official ratifications from the rest of NATO. (Currently, 8 of the 30 member states have yet to ratify it.)
And, given the importance of Russian oil and gas in the post-covid recovery period, the predictable reduction in nuclear capacity in France and Germany, the plausible lack of support from EU population and German industry for a cold winter, Putin's aging, etc... It might just be that the timing felt "as good as it will ever be".
Also, being on the "initiative" side gives your more positive outcomes. Best case was a flash invasion of Kiyv with public support. Next best case, a flash invasion without public support. That didn't pan out, but their next option is not terrible : grab as much territory as possible in Spring and Summer, then... Wait it out. General Winter will give Russia a pretty nice seat at the négociation table when EU citizens finally bail out.
Now, it's possible that we europeans stand the cold (or maybe, FSM willing, that winter is _not_ cold), that US weapons work, and that Putin contends with "I keep Crimea and some water, you join NATO, Dombass stays neutral." Sadly, that looks like the "best" plausible outcome to me - but who knows...
Whether that will count as a good outcome really depends on what follows: chaos and civil war could be terrible; a short caretaker government followed by the election of Alexei Navalny might be the best possible result.
Ukraine was absolutely not becoming a NATO member. Before Februrary, nobody considered that realistic possibility for decades, at least.
Ironically, thanks to Putin's war, Ukrainian NATO membership is starting to look more plausible (and Swedish/Finnish membership is virtually assured).