There has always been compitition for the Combat Arms. Mine was the first Chem OBC class that had West Point cadets. That was in 1993. Even then there was competition for those guys on what combat arms branch you could get.
And for ROTC it has been competitive for the combat arms for at least 20 years. The assesions board process is such that unless you are in the top 10% of your class, give or take, you won't get your first choice automatically.
Even for some other branches, its a crap shoot. I had a 3.5 GPA, prior service enlisted time as an MI SIGNIT analyst, language school, and a current TS clearance. My first choice was MI and my second choice CHEM. I got my second choice. I always thought it was a decision that was very wasteful of Army resources. But, after my carreer, Chemical has been a very rewarding and interesting time, and it was my second choice