Why the fascination with subwoofers?

IT's probably true subwoofers get a bad rap with audiophiles because in many cases they are set up in a manner that adds too much bass which can also obscure the higher frequencies.  

But like anything else, its just a matter of doing it right, using the right sub set up the right way.    

The best setups do all frequencies in music one might hear well, generally accepted as being from 20hz to 20000hz.   Older ears will lose their ability to hear the higher frequencies over time  but not the lower.

Here is one very affordable option that I would consider if needed:

https://www.amazon.com/gp/product/B00102VWJK/ref=ox_sc_saved_title_1?smid=ATVPDKIKX0DER&psc=1

Subs are simply just another very flexible and cost effective way to get extended bass when needed or desired , often in combo with smaller speakers with less bass extension, of which there are many very good quality affordable ones otherwise.

I use a fairly compact but extended 8" sub in one room which has tight quarters and with very high quality smaller speakers with limited bass extension that benefit.

I don’t use one, though I could, in others where the larger main speakers used do extended bass quite well alone.

I also don’t use one out on the deck where I run another pair of good quality smaller outdoor speakers with limited bass extension, mainly because I do not care about bass extension out there.

So like most things it all depends. Many ways to skin the cat, if needed.

Because they work.