user1457017537 No, that's not really how it works.
Firstly, not all brands buy from the Far East, many buy from manufacturers all over the world included Europe. Portugal is a particularly popular place to manufacture clothing.
Secondly, factories make up the clothing and while some do design too most large fashion brands have their own in house designers for clothing and often fabrics and textiles too, although some do buy fabrics directly from other sources. (Real Harris Tweed for example can only be purchased direct from Scotland). Fabrics and textiles are also purchased in bulk from specialist manufacturers and price does dictate cost. Actually, price full stop dictates everything. (An ex of mine is a Product Director of a very well known fashion brand. During his tenure I've noticed the quality of said brand drop as he's implemented changes in the supply chain and using different factories. Sadly the price has risen even though I know the brand is saving money on production costs. Ultimately, all brands want to make more money by trimming overheads.)
Also, many factories do manufacture clothing for multiple fashion brands, particularly at the lower end of the price scale. Even so, it's still really quite rare to find two brands with an identical product albeit with different brand name in it. However, a brand will offer multiple versions of the same dress, skirt, shirt, whatever in different prints/fabric/ lengths.
The reason why stores are selling similar looks is that no-one wants to take any risks and are producing safe styles that sales reports prove will sell through. Some still make a nod to what's being shown on the catwalks but given designer brands/fashion houses are playing it safe too, there's very little variety on offer. Also, fashion houses aren't as directive as they used to be. Where clothes shown on the catwalks of Milan and Paris once led the way, social media and the web has made fashion more democratic and chains such as Zara can have things inspired by a catwalk look instore within a week. Additionally, fashion is also cyclical, so trends repeat and certain looks win through. The same items of clothing (dress, skirt, trousers, blouse etc) are being reinvented every season. Except now most consumers expect a constant stream of new apparel. I think most fashion houses are expected to at least 6 if not or more collections a year, and most high street brands have new styles in stores pretty much every week. It's all these combination of factors that contribute to there being so little choice out there.
I absolutely agree with the PP who said you used to be able to tell a Warehouse girl, from a Topshop girl etc etc. The same can be said about most designer handbags, they're mostly all variations on a similar (Chanel) theme or else a very basic camera bag style shape with the brands logo across it. Fashion which used to be so very exciting is now really very bland and boring.
Super long post. Apologies.