Is it really the case that Android is the only option at this point for hardware makers who are not Apple? That seems silly to me. The other choice is to compete with Apple by building the whole stack. My worry is that Palm's apparent failure is going to put the rest of the industry off of the idea. It doesn't seem ridiculous to me for a company like HTC or Motorola to either buy Palm or start from scratch on their own OS so that they actually have something to sell their product with instead of just selling yet another android touchscreen device. Is that not an option?
Ex: Even if the same app doesn't run on two different OS's, they can both still talk to twitter. Back in the day, if you both didn't have a copy of Word, (and floppy drives) you couldn't share data.
Also, re: why would anyone want to do this, my answer to that is that if they have something different from everyone else who is competing on who can sell the cheapest Android phone, they would have something to sell.
Maybe the smarter play is to produce high quality, good value Symbian, Android and Windows Mobile phones that address the market.
Hardware makers today (HTC, Motorola and the rest) will most definitely go all in with Google because there's no other choice if they want to compete with Apple! I'm sure they're all well aware that they won't be able to differentiate themselves and they their margins will be razor thin, but even razor thin margins are better than no margins.