I think Bitcoin will be success in the future also, bit the buying process of Bitcoins have to be made much more simpler than it is at present. All indications point that the process will get more streamlined, so buying bitcoins will be an easy task. 
Don't just guess about bitcoin's good future. Bitcoin is created that way and the price is monthly and yearly increasing so the future of bitcoin is really there. And there are a lot of alt coins that are being compared to bitcoin but no one can ever replace bitcoin's place as this is going to be the best crypto ever.
We have all other options too, as you stated here, but none of them are trustful to me. I mean altcoins. One can invest in bitcoin very easily but can't make it for altcoins.
It seems that you are very worried about other alt coins, if you think that you can't make any choice for them it's up to you. It's also good if you are going to focus investing to bitcoin and there are times that it looks better to stay on a single coin. Well bitcoin is the main crypto currency so this is best.