Think of it as reflecting reality.

Some people don't care at all about the flair and get married extremely cheap.

Others invest thousands upon thousands of dollars for all the extravagance. Hell, some spend thousands on the cake alone.

So yeah, you can't have the fancy, expensive wedding if you can't pay for it, but you can still get married. Just like you can't have the Fat Chocobo if you don't buy the collector's edition. I don't recall seeing a hundred threads whining about that (I'm sure someone, somewhere did, but not at this level), and it's essentially the same thing.