I thought Minecraft was a 2011 release? Definitely one of the biggest games of this decade in any case, and, hot take: probably Microsoft's best investment in the gaming space since creating the Xbox. I should play it sometime.
Other candidates I could see for a title like this, based on impact rather than quality:
2011: Dark Souls
Yes the series technically began earlier with Demon's Souls, but I get the impression it really took off with this one. Now its influence is apparantly creeping into other games too (Hollow Knight, the latest Star Wars). Plus it essentially rocketed FromSoftware from a B-tier studio making Lost Kingdoms and Otogi to an A-lister capable of reliably launching new I.P.s (Sekiro, Bloodborne, the Souls series, presumably the upcoming Elden Ring too).
2012: Candy Crush Saga
Pioneering in the freemium space. People on the bus still play this.
2016: Pokémon GO
To date the most widespread application of Augmented Reality gaming I can think of. Simple, but brilliant concept, and people were so ready for this, they forgave most of its flaws.
2017: PUBG
I don't know if the Battle Royale craze can really sustain itself as a genre. Seems like Fortnite sucked all the air out of that room fast, and even big entries like Call of Duty and Fallout 76 who enter this space aren't guaranteed success.
That said, there's evidently wide appeal here. And even though the main selling point (a map with 100 players) isn't that impressive when Battlefield 2 was putting 64 players on maps in 2005, this style of gaming really connected for a while there.
Maybe it's just the perfect storm of people taking the exact wrong cue from Battle Royale/Hunger Games combined with making good streamer fodder and the less contextual violence (any plot in these games seems fairly subdued at best to an outsider like me; whereas even Quake had a whole backstory, and Battlefield/Call of Duty routinely place conflicts in larger violent contexts).
For what it's worth, I've not played any of this lot (barring Pokémon GO), so I'm clearly old. My personal game of the decade would easily be Breath of the Wild, but I think with that one we're still a few years out from seeing just how influential that one will turn out to be.