The Super Nintendo Entertainment System was home to numerous incredible video games. While many of those incredible games have made their way onto Nintendo Switch Online already, and there are a few we would still love to see come to the subscription service, there are a few that we don't expect to see on the service. While Nintendo has been great about getting its own games on the service, there are plenty of SNES games that Nintendo doesn't own the rights to. While that doesn't make it impossible for these games to show up, other publishers clearly believe these games are worth selling instead, or the license is lost to time, and it would be extremely difficult for Nintendo to make happen.

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5 NES games that are never coming to Switch Online
These 5 games may have been great on the NES, but don't expect to see them on the Switch online service.
4 Street Fighter II
Nintendo Switch Online is severely lacking in fighting games
Street Fighter II is one of the most influential fighting games of all-time, and arguably one of the best fighting games ever made. Street Fighter 2 would help fill in the lack of fighting games on Nintendo Switch Online, but it's pretty clear that Capcom will not be putting Street Fighter 2 on the subscription service. The reason is simple: Capcom wants to sell the $40 version of the game, Ultra Street Fighter II: The Final Challengers. While Nintendo has managed to get some third-party games into NSO previously, it's clear the company isn't throwing money at third-party publishers to get games on the service, unlike Xbox Game Pass.
The benefit to that is that the Nintendo Switch Online subscription is much cheaper than Game Pass, but that does mean companies like Capcom will not be putting its games on the service, even if its one of the most influential fighting games of all time and an SNES classic.
3 Chrono Trigger
Square Enix refuses to do anything with Chrono Trigger
Chrono Trigger is another highly influential game, this time in the turn-based RPG genre. The time-traveling adventure is highly respected for its great writing, fun gameplay, and incredible pixel art. It also uses the Final Fantasy active time battle and avoids using random encounters, something that even modern RPGs are still criticized for. Chrono Trigger was published by Square and is now owned by Square Enix, although the reason for it not appearing is a little less clear than Street Fighter II. It's not that it isn't understandable that Square Enix would prefer to sell Chrono Trigger, except that Square Enix isn't selling Chrono Trigger, as least on Nintendo Switch.
Chrono Trigger is not available on Nintendo Switch, nor is it on the other current consoles. For whatever reason, Square Enix has chosen not to port that game in particular. There could be plans to remake in HD-2D style, but if that's the case there is no reason for it to not appear on Nintendo Switch Online, but if it didn't happen by this point, it probably won't.

2 SimCity
EA refuses to do anything with its old games

Source: Maxis
Electronic Arts has had no problems releasing an endless supply of Sims 4 DLC in modern times, but it hasn't done much with the classic that started it all, SimCity. The original city builder, SimCity on the SNES had a few unique features, including special reward buildings and some Nintendo character inclusions. Not only does that make this version of the game unique, but considering that the original version of SimCity can be hard to track down on modern storefronts and consoles. All of that makes it an excellent pick for Nintendo Switch Online, but naturally, that would require EA to play ball with Nintendo.
Again, since SimCity isn't easy to purchase on modern platforms, it's not that EA wants to sell the game instead of putting it on a service, but EA probably wants that opportunity in the future. This is another game that falls into the same category as Chrono Trigger, where the game publisher isn't doing anything with SimCity, but that doesn't mean its coming to NSO, especially this late into the service's life.

1 Mortal Kombat II
Another classic fighting game missing from the service
Mortal Kombat II is an improvement upon the original in many ways, with a bigger roster, better moves, and, most importantly, on the SNES it had blood and violence. While the original is influential for its violence, which eventually led to the ESRB being created, Mortal Kombat II is just a great 2D fighter in the classic sense. Oddly enough, this is another example of a game that just isn't available easily on modern platforms, including the Nintendo Switch. The original publisher Midway no longer exists, but considering that Warner Brothers now owns Mortal Kombat and Netherealm is still making Mortal Kombat games, it seems like the company has no issues when it comes to licensing.
This is another fighting game to fill in that Nintendo Switch Online library, but either Warner Bros. or Netherrealm seemingly have no interest in rereleasing the older Mortal Kombat games, on a subscription service or otherwise.
It's not impossible, just unlikely
It's not completely impossible that the above games come to Nintendo Switch Online, since the games are still owned by existing publishers, but at this point, it's clear it's not happening. These companies are either already selling these games on Nintendo Switch, or are companies that don't have any games on Nintendo Switch Online. Given that Nintendo will be adding the GameCube to Nintendo Switch Online + Expansion Pack on the Switch 2, it seems possible that the company might to start winding down on the older systems, like the SNES.