Lots of reference to "the other game".
Most people don't play Falcon 4 "simply" because they like the F16. They play it also for other reasons. You need to compare the simulator overall, not only on the plane they got. I won't make that comparison here as it's not the place to do it.
From my little point of view, as soon as the F18 is released, if it is as hardcore as the F16, lots of Falcon4 crowd will come to DCS. I may be wrong, but at that point they will have an aircraft comparable to their F16, in a better looking world and with more feature. For now, DCS has no multirole of that kind to offer, so they stick to Falcon.
That you have a F16 or a F18 doesn't matter much. Most "expert" will be nickpicking the specifications difference - at the end of the day, you have two gen4 multirole.