In the US, that's certainly possible. While it is doing well, it doesn't overwhelmingly so, as it's main market is Europe. PS4 sold about 29M consoles in the US so far, with a peak of 5.7M in 2015 but generally around 5-5.5M each year.
By contrast, Switch sold 5.5M consoles last year, 4.8M in it's launch year and is currently tracking ahead of last year, so it's certainly keeping up with the PS4 right now. Unless the Switch get's cut short or crashes in sales like the Wii did, it certainly has a shot at outselling the PS4 in the US.
Yeah I've noticed that sales in Europe aren't as good as the other countries, it's passed lifetime PS4 sales in Japan, right? Though if it has I'd assume it's because of the portable aspect since the Japanese market goes crazy for that. Thank you so much for the reply!