True! It's still a useful product, but the pressure to keep getting huge-r is always there I guess. I knew someone who worked there and they seemed pretty desperate for new initiatives (like the failed Paper). Most of their competitors have online storage as part of their product portfolio. I don't know of anything else major that Dropbox does...
There is always room for a smooth paid service compared to the rough free one. Android and Linux vs twice-more-expensive Apple.