I guess you did not get the hint when they named it cryptocurrency instead of....cryptomoney.  It is a currency; it's not money.  Currencies are generally always a bad investment on a long timeline and there is no reason to own them unless you actually use them.  Once the market cap tops out, whether that's at $1200 a coin, $200 a coin, or $10,000 a coin, everyone who was attempting to use it as a store of value is going to flee the ship to the base of Exter's pyramid (metals) since they are a superior store of value, while the only people that continue to hold coins will be the people who actually use it as a currency.  

The number of people using it as a currency will obviously be factored by it's throughput (TPS).  To have a high market cap as a currency, TPS would probably have to be drastically higher than it is now with something like a functioning LN and 5000 TPS.  At that level it could probably float a large market cap as a payment processor, but I do not see a currency functioning well at low TPS with 1 MB blocks and no segwit or LN since low TPS is counterintuitive to how a currency is supposed to function (high turnover, not based on being a store of value or generational investment).