While the economy may be a factor I don't think it's the main factor comparing last year to this year. I think many companies and organizations have woken up to the fact that over the past few years flying discount, renting cheaper and staying in lower tier hotels did not change their productivity at all. Like the last line of the story says
More than half say that a hotel's amenities have a greater effect on their ability to work productively than do those connected with airline flights or rental cars. Free hotel Wi-Fi is an amenity that about 90% say is important.
The assumption that expense reports will go back to a level they were a decade or whatever ago is probably something the reporters should give up on, I don't ever see companies going back on those in large enough numbers to make a difference.