I expect GT Sport will be between 550k-600k (total) by the end of the year. It really depends if the title is part of soft bundles when stores are adding value to other big bundle releases (GoW, Spider-Man etc.), plus Black Friday and Christmas.
The interesting tidbit from GamesIndustry.biz is that PS4 software sales are only 7.8% down year-to-date, which paint a solid picture considering last year Q1 had Horizon Zero Dawn, For Honor, Ghost Recon Wildlands and also more contributions from a bigger number of console exclusives such as Gravity Rush 2, Nioh and NieR Automata (versus Shadow of the Colossus and Ni no Kuni II this year).
God of War release is most likely going to turn around that year to year drop.
Yeah I don't think that Nintendo realise that the 1-2 Switch adverts actually put a lot of people off buying a Switch. They're truly dreadful and pure cringe and make the Switch look like nothing more than a novelty. Nintendo UK did 'casual' adverts so much better back in the Wii/3DS era - I remember Ant & Dec etc.