Only if you assume "can play all jobs" to be the same thing as "can play all jobs and have the same best gear for all of them at the same time". They're both very different things. Nothing has contracted itself unless you throw one into it.
It's not like buying a single piece of Esoterics gear locks you out of the other jobs until you finish. You can play all of your jobs whenever you want to: that's what the system is about. It isn't about being the best geared with everything in the space of a few weeks (that's how MMOs keep you going).
You have to make the decision about which jobs you want to focus on. You can either focus on a single one and pour all your time and resources into that or spread yourself out and gear up several at the same time.