Whilst I agree that the O'Neills kit and leisure clothing has generally been of a pretty rubbish designs and quality, the club must take blame for this.
As with any sporting company, the club have to sign off on all merchandise from both a design and material perspective. Without that sign-off the clothing manufacturer wouldn't touch it.
My daughter is a fashion designer and has worked for companies such as Umbro, and quite often the design company will try and cut corners to save money, etc - if they can get away with using material that only costs them £X instead of £Y but are still getting the same cut of the selling price, then why wouldn't they try it to make a higher margin. Also, from a design point of view, if they can knock something out with minimal effort, they don't need to employ as many staff because they don't need to spend as long on each design.
It's up to the club itself to police this and kick back where they think either the design or the quality of the merchandise doesn't come up to the standards that befit the club, something that Saints sadly seem to be lacking in.