Dropbox and Evernote, for me are two very similar companies. Startups that innovated on a great user experience and had a flawless execution in the beginning. I was an early adopter of both of them, and they worked well. Dropbox sync between different machines worked like magic. I still remember some of the nightmares my coworkers had with OneDrive in meetings when the files for the presentations were missing because…
I don't think there's a single example of a company where >90% of their userbase if free, and they succeed after making the free user experience worse. They're thinking in terms of money (or reducing costs), but the other view is that they're making the experience for >90% of customers worse.
What dropbox seems to forger is that many of their enterprise contracts happened precisely because the decision makers used dropbox personally, and liked it. By screwing over your free customers, you are actually only hurting future sales.