Feedly probably isn't claiming those numbers with any basis in reality. In particular, many people made Feedly accounts in a hurry out of panic when the shutdown was announced. Having used both, I highly doubt users of Reader are still regular users of Feedly.
I'm a former Reader user and now use Feedly. What do you use that's better than Feedly? I settled on it since it was "good enough" but I haven't invested the time to explore other options.