You made some quite interesting points here but I beg to disagree on having Bitcoin is more valuable than Altcoins. What can made through altcoins can never be compared to what holding btc would give. Holding altcoins with good project is far more important to me than holding btc... No doubt the market will experience some good btc movement come August, which I know would also proper good project altcoins to hit ATH.
If I planned on buying some coins today. Which would be the better long term investment, and why?
If you want a long-term investment then bitcoin can give us an advantage. Different from altcoin, usually altcoin will not last long enough and sometimes also if we choose wrong then altcoin usually experience a drastic rate reduction. While bitcoin has an increasing trend every year, so you do not have to worry about bitcoin values. If you can be patient then you will get a huge profit. Especially at this time bitcoin will change in early August, many say that the beginning of August will be an increase in bitcoin prices. So do not ever be afraid to invest and have bitcoin.