I don’t think that’s the case they probably have had at least a small team working on this before the Steam deck was announced. I don’t think the audiences overlap that much to be honest and the two devices have different use cases.

The steam deck is just a powerful hand held computer (relative to other gaming hardware is pretty weak though) that runs PC games with all the ups and downs that come with that. I think there are number of steam deck buyer that are not that familiar with the underlying hardware that are going to be disappointed when new games are not going to run acceptably on it. Where as for the switch/switch 2 games will at least run acceptably