Actually, as Bitcoin's value and "market cap" has increased it has become more stable. The current fluctuations are small compared to what used to happen. If the value continues to go up (it is still up 30% over 30 days), stability is likely to increase as well. If not, it won't.

I'd also like to point out that "real" currencies experience large fluctuations sometimes too, despite their much larger "market cap". The pound, the Swiss franc, and the ruble have all seen large fluctuations in recent years. And of course there have been many cases of hyperinflation in the past and we have a current one in Venezuela.