No, never. Personally, the better graphics and frame rates aren’t even the primary reason I choose Steam, just a side benefit.
The first reason is that many games are best played with mouse and keyboard. I wouldn’t have bought Doom: Eternal on Switch even if it was 10x powerful as my PC unless the Switch had a mouse and keyboard.
The second reason is that the Switch eShop will one day die. All the pre-Switch Nintendo eShops are dead, or soon dead. Steam is 17 years old, and shows no signs of slowing down. If I buy a game on Switch, it’s likely that someday that game will be permanently gone, and I will not be able to re-download it. If I buy a game on Steam, it’s somewhat likely I’ll be able to re-download that game even on the day I perish from this world.
But that’s just me personally.
If you want actual game sales figures, they are very hard to find detailed comparable information without paying money to various services. But what meager data we do have suggests that Nintendos game sales are ludicrous compared to the competition.
Just a couple months ago only the newest and hottest games like Resident Evil: Village could beat out Mario Kart for the Switch. A game that is 4 years old and was also released on the Wii U. And that excludes all the digital sales on the eShop. Just the cartridges.
Look up any publicly available recent video game sales figures. By any measure, Nintendo is the champ, and it’s not even close.
There’s a pie of all people who buy console video games. SONY and Microsoft compete for a slice of this pie labeled “hardcore”. Nintendo owns the entire rest of the pie and absolutely nobody competes with them for it. Some people in the hardcore slice also have Switches just for Nintendo games.
Why are you asking why Nintendo doesn’t fight harder for the slice where SONY and Microsoft are squabbling? Why not ask why SONY and Microsoft leave Nintendo entirely unopposed on the entire remainder of the pie?