The original Bitcoin protocol is very innovative. However, there are several reasons for why today's cryptocurrencies will fail:
1. Too slow transaction times for general use.
2. Too bloated block chain for mainstream adoption.
3. Having to store coins "under the mattress" is a step backwards.
4. Proof of work will lead to too large transaction fees.
5. Proof of stake leads to the rich getting richer.
6. Lack of government support prevents mainstream use.
7. Trading against ordinary fiat currencies causes volatility.
Your're assuming that All of today's cryptocurrencies are made for one purpose, to infiltrate the mainstream population which is not true. There are many niches that Needs to be filled in the cryptocurrency secter.
For ex: One niche would be a store of value coin, another would be a privacy/anonymous coin, etc.
If that was true, we would have seen a success story by now. Bitcoin is a success for investment and currency trading, but could be a limited one. We will see. I stick with my prediction that the bitcoin price will not go much higher than $5,000 because of lack of mainstream adoption.