My view is Bitcoin is going to be the store of value and for large transactions.
We see people buying cars and houses with BTC....so while the transactions might be down, the amount of those transactions will be up. This will continue over time I believe. Companies will pay their overseas suppliers in BTC, but people will not buy a cup of coffee with it.
BTC and ETH both have scaling problems which they will solve to a degree but have a tough time hitting close to what STEEM, BTS, and EOS (when it comes out) are able to hit.
This is going to be a major hurdle for those tokens.
In other words, Bitcoin would be like the "Gold" of crypto. However, a lot of this depends on the performance and feasibility of the Lightning Network, not only in Bitcoin, but other blockchains too. If LN works as intended there will be a major shake out of altcoins that don't use it.
Fortunately, my holdings in Alts, at least my two biggest, are STEEM and BTS...two that dont require lightning.
But you are right, I see BTC improving with SegWit and Lightning...it will not be this old grandpa animal people are trying to make it out to be. Also, as you stated, as gold, transaction time is less important. Does an overseas supplier care if it takes an hour to get $125K in payment versus 3 seconds? The banking system takes days.
Agreed, I see there being many crypto-currencies that each do something in their own way unique and well. However there does still need to be a central currency they are all based off of which I feel will end up being BTC.