That all obviously depends on how you define failing, and we simply don't know what criteria is being applied. At Google the criteria was catering to Google Earth and he obviously did that... to the point where those were the only parts of SketchUp proper that saw any real growth.
Trimble is a big question mark -- all I can gather at this point is that they don't care for SketchUp to be a mainstream modeling application (even in the Pro iteration). Otherwise I would have to assume something would have been done in the last 2 years. It does not take 2 years to implement new modeling tools no matter what the circumstances.
So, I guess a more accurate assessment is that he is failing to lead SketchUp to anywhere I find worthwhile. I would say from many of the comments (yours included) that many other people are disappointing in the directions it is going as well.
So at the end of it, he is losing hearts and minds of the users (at the very least) to the competition. There is certainly some inertia that has been propelling the product forward based off what happened a long time ago (already implemented or in progress features of the software from before). But I really can't believe that any recent moves have netted significant amounts of new users.
Really what I have seen is alot of promises of cool stuff to come, without any specifics given, and without anything of merit materializing. It is easy to make promises, but you have to deliver something eventually, or the credibility of those statements becomes suspect as simply being delay tactics.
I mean of course Trimble is happy with the financials -- even if you only count existing Pro version users, they are paying double what they used to pay for upgrades... and Trimble doing (or perhaps releasing) hardly any work to get the increase in revenue. So I am sure the financials look spectacular.