You only need an extremely rough estimate of future value to make this a good investment as long as the estimate is several orders of magnitude above the current price.
The collective mind of the market obviously does not believe in that...
lol @ perfect market theory. There are endless examples of why that theory is as flawed as can be. The market is retarded (every market is, shallow markets more than others) and there lies the opportunity to buy assets for less than they're worth.
The reason that BTC is so cheap and progresses so slowly is that people are only exponentially "getting it". As long as this persists, however, it will grow exponentially, and unless you can't wait for 2 years to see the results, then ....
...you should ANYWAY buy all the bitcoins you can, because historically it has been the best investment in all timescales.