As much as the Switch launch impacted the PS4, so barely, if at all.

A little, but the Switch is more affected by the general motions of the consumers and their market than the specific machines and/or platforms actually on it. We're seeing a surge in sales of consumer electronics right now, an unprecedented one, the curve is almost upside down for some. Once the market returns to normal, contemporary trends and market movements will affect the Switch like any other product in consumer electronics. The period of March - June is an anomaly on most sales curves in this segment, this is not the normal state of affairs for these devices.

Nintendo has built a platform that stands somewhat to the side of the PS and Xbox mainstream middle, and as such won't be impacted all that much. News value and coverage will certainly be a factor though. As it stands, the Switch is overall not a natural option to PS and Xbox, and vice versa, the various market segments are correlated but not very closely connected.