Reactivity is to be expected from the entrenched player, but aping competitors alone won't keep Google relevant forever.
Google implemented vector maps on Android long before Apple introduced their own maps (i.e. ~years). Likewise, 3D buildings have been available through Earth for years, and rendering them in Maps was an obvious next step. Ultimately, both Apple and Google launched 3D at right around the same time.
Last, as a sibling poster pointed out, if you think all of this was started in reaction to MapBox's work (earliest public mention I found was April 1st) and completed less than 3 months later, then that's just fucking admirable execution right there. But alas, that probably wasn't copied either.
I don't think it's impossible cloudless aerials were inspired by MapBox though... I think you and your sibling overestimate how hard it is to chop up and process imagery with a cluster of computers.
If you seriously believe that _any_ mapping provider (including Microsoft, Nokia, or Google) hasn't been actively removing clouds from their imagery for a very, very long time, then you haven't been paying attention. No one needed MapBox to give them the idea of removing the giant patches of white obscuring everything in view.
In any case, your willingness to comment on a subject that you obviously know little about -- and then extrapolate your wrongness into a statement about the industry -- is impressive. Every sentence of your original post is wrong.
I was chatting with my colleague at work today, who actually stood up our landsat servers and does all of our tiling work, and he thinks that the pixel-averaging technique to de-cloud the images was an innovation that was pretty unique to MapBox. According to this article, they noticed a guy doing it in February 2013, and hired him right away to do it for them: http://www.wired.com/design/2013/05/a-cloudless-atlas/.
MapBox got to market with it in just a few months, and it's a particularly absurd argument to say this was too hard for Google's hundreds of maps engineers to implement. I heard at the State of the Map conference that it was just a few guys working on it at MapBox. Given Google already has the imagery, and the processing pipeline, I think adopting this declouding technique was actually a piece of cake.
Also, while Google has been removing clouds from their images for a long time, I think their technique has been to pick the best of many images. Their imagery used to have many more clouds in it, until all of a sudden.
http://www.mapbox.com/blog/cloudless-atlas-with-landsat/ http://www.mapbox.com/blog/huge-mapbox-satellite-update/
Google Earth had 3D for a long time. Vector maps is again a huge undertaking and takes time to get right. Some companies didn't take their time, some did.