Good discussion on the topic here already, for sure. Why pay more for something that does the same job? Is it like the old side-by-side "blind taste test" of different brands of cola? If you really can't tell the difference, then of course, why would anyone pay more? (though many happily will do so for political / economic reasons) (oh, and of course it's okay if someone wants to may more for a certain brand, just because they like the brand)
But honestly, if you handled an Aimpoint Micro side by side with your Romeo5, I'd be very surprised if you didn't notice a difference in quality. Whether the difference matters to you, that's really up to each individual - But the difference is certainly there. And it certainly matters to some people. Is some of the price difference due to marketing, etc.? I don't know, probably, but also I don't care - For me the decision is whether or not the difference in quality justifies the difference in price. For me, and for my application.
There is something to be said for having an optic that you really never, ever have to worry about. If I was still doing "serious" 3-gunning, I'd still have an Aimpoint Micro on my primary long gun. My needs are generally much more casual now, so the Romeo5 works well enough 90% of the time. But also I have a higher quality (and yes, more expensive) red dot for the other 10%.