I was thinking a lot about Dash future but I can't say that it will succeed. Amazon, PayPal, ebay, Alibaba etc have their own user base and they can issue their own digital currencies/assets. I think that the sharp rise in Dash price is influenced by Bitcoin scalability problems. Dash goes into a bubble with a lot of FUD and hype around.
Regarding Bitcoin the main problem in the future is not a confirmation times and price per payment. The main problem is BTC network itself. We can agree that it is the safest blockchain because a lot of miners are involved. But miners are not for safety of network they are for profits. This scheme works only way - miners are interested to mine and only will do that if reward is bigger than expanditures. Mining costs a lot today and will cost much more in the future. It means that to run Bitcoin network is very expansive and it is a question how profitable it will remain. Customers and companies are unsatisfied with costs of TX's. BTC doesn't reflect the needs of business and customers. It only reflects the needs of speculators. Because of that, if anything changes aren't introduced in the future, it will fail and people will choose other options. But I don't think that Dash will change BTC. I have another favourite.