MLB The Show has seen a massive increase in FW sales, 15 did 200k FW, 16 did 237k FW and 17 apparently did 612k FW. A massive increase with 17 for some reason, so it wouldn't surprise me if the trend continued and 18 had an even larger first week.
But weirdly this trend doesn't lead to an increase to lifetime sales...
A word of warning regarding 17 - that's undertracked after the first month iirc, I'm just getting the charts more up-to-date before I find the time to go back and make the 2017 adjustments. So in that case the launch increase (and dropping PS3 support) will have led to quite a nice overall increase for the PS4 version lifetime.