No it's not. It's their big games for the next year. You start the hype machine for that shit early. Not to mention we don't know what Sony will show anyway. The whole statement comes across as "we are not ready to show off these games. Wait more." Plus E3 is Gamescom times 100 so MS winning would be nothing compared to E3.
First, we do know what Sony will show at their Gamescom conference. Nothing. A company who understands good strategy is one that plans for what they
do know, not what they don't.
They don't know what Sony has at E3, but it's a fair bet they'll have some big announcements and some of them will surely drown out some of Microsoft's smaller announcements, just like some of Microsoft's big announcements will do the same to some smaller Sony announcements.
Games like Scalebound are big to
us, but it's a Platinum Game... their titles never sell a huge amount relative to the 'big AAA' titles, and so it's the perfect game to debut at a show like Gamescom when Microsoft can
depend on Sony not being there to drown it out. Similarly, Crackdown is on a AA tier of game judging by sales, which makes it yet another perfect candidate for a show to Microsoft's own. And Quantum Break is a brand new IP from Remedy who has been hit or miss with their games in terms of the attention/sales they've received, and the title has already had a huge coming out party multiple times... and it was also delayed out of 2015. It's yet another perfect candidate for a show to itself.
This is a brilliant strategy. It really, really is. They will have games at E3. Microsoft will have a packed show just like Sony. They will show their new Forza, their Gears of War Collection, and all sorts of surprises. They have big stuff in the pipe. And that will be at E3.
But then they smartly now have a huge summer show to themselves, where they can highlight their second tier of products without any of them being drowned out by overwhelming E3 press coverage of a billion different products.
I do the E3 summaries each year on NeoGAF, and the number of announcements each year is staggering. It's basically impossible to keep up with. Microsoft has in my estimation made a very very clever strategic move.