This company might be different because they demonstrated their ability as IPFS is fleshed out but as others pointed out Filecoin is a different beast entirely and they are basically starting from scratch again.
The higher end of 6-18 months of pure dev time is a long risk range to get an untested product out. But I guess they have plenty of runway now to work on it with this massive ICO. Let's just hope they don't spin their wheels forever in research mode and spend their time and money wisely.
It's entirely possible someone else figures it out before them and this play will be a game of scale. I've heard this idea from more than one person well before Filecoin was around.
There are occasional exceptions [0].
[0] https://venturebeat.com/2017/07/25/khosla-ventures-leads-50-...