Yes and no.
Unfortunately, you are joining firms that embrace the generalist model. If you are coming in as a consultant or lower, you're going to have to be a generalist (I didn't know anyone who specialized).
That said, there are two caveats:
1) Platinion / GAMMA are obviously specializations you can join
2) you are still very much naturally allocated to the things you know due to the process of "natural selection"
Elaborating on #2, there is a "matching process" that occurs to staff projects in the pipeline. The staffing manager tries to put you on projects you'll do well on. Partners/Principals pick consultants they think they will do well on.
As such, your prior history absolutely influences the projects you get put on (whether they admit it or not). Anectodally, almost all of the projects I was staffed on had an IT/Agile element to them, because that was the expertise I had coming into the job!
So, yes and no to your answer :)