Mate, I don't really understand that you said the price won't be very volatile when the market cap grows high. Does the high market cap really decrease the volatility of Bitcoin? 
Well, I'm not an economic expert but I guess when Bitcoin's market cap grows to 100's of trillions in future then it's volatility will reduce. The more market cap might help to reduce the volatility of Bitcoin and their might not be similar level of dips when market grows by a huge level. Let's say if somehow Bitcoin grows to 100 Trillion market cap within 5-10 years then that might help to reduce the volatility of it.