HTC's decline continues: a short spike upwards at the beginning of the year after they launched a solid, coherent portfolio, has been followed by a return to rapid decline.
As seen with the Palm Pre and Nokia Lumia, good product is no longer enough for success in the handset business: you also need scale. Samsung's run-rate annual marketing budget is now $11bn, which is more than HTC's run-rate annual revenue of $8.4bn. Even though HTC is plugging into the ready-made Android ecosystem, an advantage denied to Palm and Nokia, the product still isn't shifting.
I'd suggest that the largest real threat to Samsung's 50%+ share of Android units comes from the cheap generic Chinese (based on Mediatek chipsets), and to some extent the Indians, not the other branded OEMs.
There are so many challenged handset OEMs (Nokia, RIM, LG, Sony, Motorola, HTC) that some sort of roll-up strategy sometimes gets talked about, but it's hard to see how M&A would really solve the problem. And of course the US concerns about security almost certainly mean that Huawei and ZTE can't act as buyers, which would otherwise be the obvious next development.
The only vaguely plausibly buyer I can see is Microsoft - there are plausible reasons for it to buy any combination of Nokia, RIM and HTC, but equally plausible reasons not to.