The quality of published apps on WebOS is questionable (there are probably both great and very poor developers out of those 1,000). What Microsoft is telling people, in contrast to HP, is that they are not intending on abandoning their phone strategy anytime soon, and are willing to go through great lengths to woo developers over. At the same time, had this offer been extended to iOS devs, they would've had a great response rate for hardware, and it would still remain to be seen whether anyone would actually start developing for Windows Phone.
This does add another way to analyze the hardware-ecosystem tradeoff that people are considering with the Touchpad fire sale: what's the sweet spot for burning money in order to build a thriving ecosystem?