A game by current definition typically involves a pastime containing rules and victory through skill.
That definition would remove a whole lot of games from the umbrella of games.
The Sims has no victory condition or really any rules. The closest thing to a victory condition would be getting your character to the top of their career, but you can change careers on a whim.
Sim City has no victory condition or really any rules. The closest thing to a victory condition would be getting your city to whatever point you arbitrarily decide makes it complete.
Animal Crossing has no victory condition or really any rules. You can utterly ruin your town but keep playing, and you can build everything requested of your villagers but they'll keep asking for more and more and more.
Echochrome has a victory condition of navigating whatever level you're playing, but there's no end of levels, no benefits gained or anything awarded or even changing when you beat a level. The game is the same if you only navigated one puzzle as it is if you've navigated thousands.
Minecraft. Just...everything about Minecraft.
As for skill, plenty of games anymore have various levels of difficulty. Some games, when played on easy, are pretty much harder to not complete than they are to complete.
There's also the aspect of online play. Skill can be meaningless if someone learns what's overpowered or flaws the design and exploits it. You could say that's a skill within itself, but that seems a bit like cheating the definition.
Further, walkthroughs have been a thing since forever. Some games REQUIRE a walkthrough due to insanely convoluted plot devices that nobody could be reasonably expected to figure out on their own due to lack of any information from the game itself. There's an entire TVTropes page dedicated to just those games. If someone beats a game only because of a walkthrough, are they exercising skill? Was skill required for that victory condition?
Don't forget about the influence of randomness, either. Monopoly is a game, but no amount of skill will ensure that you always, absolutely win. My family owns six different kinds of Monopoly and I've played the game my entire life. But I can still lose completely due to chance of the draw or roll of the die.
And back to the online aspect: World of Warcraft. I really, truly find it hard to believe it fits the concept of a game by these standards. You can play the game for years by doing nothing but side quests which involve no skill other than killing 10 frogs to get two mystic frog farts. There's no requirement to participate in any raid or to defeat any enemy or boss, just the option to do so. And if you do any of those things, nothing changes and you can do it again and again and again.
Or, EVE Online. Entire corporations exist within the game, but there's no win condition. They can battle each other and destroy each other, but neither wins the game. And no matter how strong the corporation gets, other players can play 80 hours a week and never once have to encounter or deal with that corporation. You can effectively spend the entire game just mining, which involves as much skill as making a peanut butter and jelly sandwich.
The point is:
Gaming is impossible to define in a way that doesn't exclude games that other people consider games. Visual novels have been a thing since forever, but they're still considered games by plenty of gamers. Sim City has been around since forever, but it's still considered a game by plenty of gamers. Most of the games I listed here are probably older than half of the gamers on Reddit, and likely considered a game by most gamers on Reddit.
That's why genres are a thing. In a perfect world, we'd describe any media you engage with on a computer/tablet/phone as Interactive Media, and each type would have its own genre without the word Game being included. And that's because a lot of games that are considered games have very little game involved in them, especially with the rise of open-world or end-game content. There are even people who think Metal Gear Solid's second and fourth entries don't count as games because 80% of your time engaging them is watching cutscenes and dialogue. I don't feel like I've gamed after completing Arkham City because I'm still in the city, able to do whatever I want, and 99% of my playtime was just mashing a button when prompted.
So, realistically, it would be better to do away with the genre of Video Game and just consider everything Interactive Media because that's what it is. You can have an Adventure genre and it can include Shadow of the Colossus right next to Gone Home. You can have a Management genre and it can include Civilization right next to Sim City right next to Animal Crossing.
But that also would involve making discussion a little more difficult. So for the time being, we've accepted that "gaming" perfectly encompasses and acknowledges all of those things.