The issue with Carousel Boutique isn't that the product isn't that the product isn't good, but that there is a lack of demand for clothing stores in general.
Drive up business for Carousel Boutque by instating a law that bans public nudity.
Why not giving those who wear clothing a tax break?
That way they still have a choice, but one is less costly than the other, causing the ponies to drift naturally into clothing.
Or we could create a series of advertisements that encourage ponies to buy clothing.
Maybe perhaps create a law which states all folk currently visiting or living Canterlot must wear one article of clothing at a minimum at all times. Undergarments included.
>seeing a stallion wearing tight, feminine underwear, hugging on all the right contours, occasionally seeing his anus clench whenever a cool breeze pops up