Seems like there's not been much evolution in the last couple of years other than the emergence of Tern. Dahon is largely back where it was in 2007 having given up most of the Biologic bits and pieces. Brompton seem more interested in accessories than improving the core bike design which still has certain flaws. Prices keep shooting up each year.
I wonder what sort of market share folders will have to have before the big bike companies take more interest, and what will happen should that happen.
A couple of Giant's recent bikes look well thought-out and er, 'serious' in design terms rather than just being rebadged Dahons, though Giant have had their unique models for years, so I don't suppose there's evidence there of a big player moving in.
Brompton seem peculiarly positioned as their folding design and brand are one, yet the fold isn't protected by patents. Should a large company choose to move into the market they'd be starting with a clean page, able to correct all the small deficiencies that Brompton appear to be stuck with in order to keep up spare part compatibility. I've seen it happen in the software world; small companies develop innovative new products only to see those innovations, erm, bought out (if they're lucky) or stolen by big companies. In the bigger picture it seems their role is often simply to agitate the market. I wonder if in 10 years time it'll be the same for smaller folding bike companies.