I seem to recall the trailer we saw at PGW was never intended to be shown there, having been pushed forward at the last minute from the PS Experience, I'm guessing to capitalise on the whole FIA/Bugatti/France thing (and the fact that Europe is probably the biggest market for GT), which is why Jordan initially warned us "don't board the hype train if it's headed to Paris". He then said, if I'm not mistaken, that he was unaware of the plans to show GTS at PGW.
That might explain why there's been such a long gap between the first trailer and the second - if they had some sort of schedule of trailers and what not, and simply moved the first one forward without compensating for the time difference (and leaving the second trailer to be released whenever it was initially planned), then it would mean we would be waiting a long time for the second trailer. If GTS had been revealed at PS Experience, we would have seen the first trailer only a month and a half ago, rather than three months, which would be a less arduous wait, if you will.