Copying a distinctive idea or design feature, though unprotected, is an undisguised way of grabbing market share using ideas put into the market in the first place by innovative competitors. That happens all the time. Though it be standard practice for companies trying to grab customers, it remains a disgraceful practice. That said, I bought an Asus Zenbook. Afterwards I found out it was a copy of the Mac Air. I wasn't impressed.
So in other words, you'd rather be paying double or triple for a Mac(book) Air? I guess that's would be my textbook definition of a first-world problem.
In case you did not know, the recently crowned world
#1 manufacturer of mobile phones is XiaoMi, a China-based company who sells cheap, low-to-mid-specced Android phones in a rather unique way. One of the guys hired to head its overseas expansion is an ex-Google VP, and they show no sign of slowing.
Few people are going to mourn if Apple or Samsung loses out because they blinked. The same should apply to Brompton.
There's a very good reason why copyright has a time limit. Being stubbornly subservient to the concept of it only serves to keep prices high and innovation low.