You are missing the point.
This is branding.
"Office runs into tens of millions of lines of code."
I am aware of that - my father doesn't give a shit. He wants "to download Office". I know it takes a lot of time and investment, but even if they released a subpar editor that was able to view it, they would have got his money and I highly doubt he would have complained.
"Porting it to webOS is a laughable proposition with the amount of devices it sold."
I agree, and I understand why they wouldn't. My point is that they lost a recurring customer by not creating it. Think of it similar to the police response to a bank robbery. I can guarantee that the cost of the response is several orders of magnitude greater than amount even in the bank, let alone what the thieves are actually able to steal. That is because they are not reacting to the cost of the money being stolen, but to the long term costs of making it seem like anyone can rob a bank. If Microsoft made an App for EVERY platform, regardless of cost, it would be hard for anyone to even penetrate into the marketplace, therefore ensuring longer term success.
Secondly, Microsoft loses over 2B a year with Bing. They are a huge company with very deep pockets, and I highly doubt hiring a few dozen swissarmy programmers would make much of a dent comparatively. Theirs is not a finical issue, but one of leadership, and culture.
"And calling it an 'app' is disingenuous, it's a full fledged suite."
Agreed, was only done for the sake of brevity. Easier than writing "an office app, a powerpoint app, and an excel app"
"Do you know there they aren't already working on Office for the iPad?"
Yes, several /years/ after its initial release, despite making up over 90% of the tablet market. Docs to go, a fully featured suite, was released within a couple weeks.
"After all, they seem to be actually bundling Windows 8 ARM tablets with Office applications."
Not sure what you mean, iPad !== Windows arm tablets. And again, everyone expects Windows software of windows hardware. The discussion at hand is Windows software on non windows hardware, which is how they made their millions to begin with.