People in the BOINC community are running far more powerful setups, completely for free (i.e. they haven't joined Gridcoin yet). There are 500k active BOINC crunchers and over 4.3 million registered BOINC users. So yes, there is a lot of room for growth. Not to mention that, for the general population, the idea of computing for science is far more understandable and fascinating than repetitive Proof-of-Work hashing (which has zero benefits except securing the blockchain and is therefore difficult to understand for non-crypto people).