Exploration is an infinite process. We have been exploring our planet since her inception and continue to do so. I am not too sure as to whether our knowledge of space overrides our knowledge of the planet, but I am do sure about the reasoning that if it wasn't for the constant exploration by our ancestors and for that matter even the present generation of the humanity in general, we wouldn't be where we are today.
Have we ever wondered as to why space exploration is always fascinating for us humans? That's because of the supposition and to a certain extent the certainty of discovering life form in other planets! It's with this sole motto that all the space explorations are motivated and inspired for!
As far as funding goes, let's not look at the budgetary allocation on an annual basis! There are millions of organizations, apart from the government, which sponsor and fund land explorations on our planet and if you combine them all, the total funding devoted for land exploration far overrides those of Space programs. Since space programs are a domain strictly controlled by the government with no encouragement or opportunities to the private sector, the funds allotted does seem more to a common man, but in reality it is not!
We do know a lot about our oceans and new species are being discovered on a daily basis. Since such discoveries appear late to the common public, we come to the erroneous conclusion of not much being done on exploring our own planet!