this is really simple;
you buy a curtain pole..
you buy a cheap one from pound stretchers for use with your flimsy cheap pound stretcher curtains, all is well.
you hang heavy good quality curtains off it, it breaks...
then you buy a solid curtain pole from BnQ.
curtains never fall down.
whats the lesson here?
the less you pay, usually the cheaper the materials and workmanship becomes.
The more "heavy" your use of the item the more it will cost as you dont fall into the normal "cheap" bracket of customer and the more workmanship and better materials are needed.
To ensure customers arent being cheated, companies build up brand names, under these brand names the companies spend large amounts of money to be inspected and approved for particular engineering standards (eg. ISO) these standards protect us as customers as we know what we are getting every time. (You can look up the accreditations of each company and their products free of charge.)
But yes, the companies who have put the money in for R&D and quality will attempt to make a larger return for the financial risk they have taken, they do this by charging a premium for their premium products.
This isn't intended to reflect on any supplier on this thread, just to explain the reason behind one brand being more expensicve than another.