Old games are more singleplayer/story/sandbox inclined
back then i could play whole day without even connecting to the internet, just loading a game of max payne, playing the sims, hitman 2, or playing red alert/generals/warcraft, satisfies me.
I play my consoles, same thing happens. Tenchu, Tekken, Syphon Filter, Metal Gear Solid, Romance of the Three Kingdoms, were the best games I've played. when friends come, we play some coop, split screen games. I use my internet more for downloading mods or checking guides/cheats than playing with other people.
Newer games are more multiplayer/online/profit inclined
Better Internet connectivity has exposed us to online play, that you can also play with other people online. its a double edged sword, while playing with friends is a good thing, it has depreciated the enjoyment i get from playing single-player games, sometimes i get that longing of wanting to play with someone. But most of the time it has something to do with HOW they make their singleplayer games nowadays compared to multiplayer games. one perfect example is Battlefield 3 onwards; while the multiplayer is definitely a fun game, they completely missed the chance of singleplayer awesomeness by not making a multiplayer game with bots(BF2 style), they relied entirely on the campaign, which was short and not that good anyway.
this only happens on the AAA side though. on the indie side, things are looking much like the old days, which is nice. there are many games that are still really good singleplayer today, some even has a surprising multiplayer option in case you wanna play with friends.
realistically speaking It is better now than it is before, there are more games now and it caters to more people. its just that you get exponentially more shit nowadays that you think this is all worse than the old games. plus its hard to fight against nostalgia and childhood.