Hi Bill,
My guess is, that it's mostly because of the Mirror Modifier for the speakers, but you could also just keep it one Object (Add the speakers ad holes in Edit Mode, so that they're part of the Console already), if you want. There are always more than one way of doing things.
I'd say there wasn't a big reason, just that that was how it came out. One of the things you get the hang on in Blender is that there's a ton of ways to do the same thing. Some ways are more efficient, some ways are the same, but your brain is not always in the most efficient way state all the time so you just do it with whatever occurs to you and then after a while you're like hey, I should've have done it this other way. That happens all the time and there's no really right or wrong way, you're just trying to make it happen.