Yes and it's not supposed to. Steam Deck vs Switch is similar to PC vs Consoles in the sense that yes, both can play games but that doesn't mean PC takes away from console sales.
The Steam Deck is for those who want more than what the Switch offers and those that have the money to pay for it. Not as a competitor but as more of an enthusiast device. You can see this in not only the price but in design as it's not targeting something that "the whole family can enjoy" but rather the PC gamers that can make use of all it's functionality. You can give the switch to your kid, to your grandma and whoever and they can easily pick it up and play. The Steam Deck on the other hand, you need some amount of PC knowledge to really make use of it and that's not a bad thing. It's why I already own a Switch and I pre-ordered a Steam Deck.
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