Most altcoins are just pump-and-dump schemes. But there are a few ones that are really trying to do novel things: see for instance Zcash and Monero (anonymous transactions), or Cardano and Ethereum (Turing complete smart contracts and PoS). Bitcoin is not trying to do those things, and I personally believe that's great (Unix philosophy), but there is no reason why others shouldn't try to develop solutions for a different set of problems.

My last Bitcoin transaction cost me a bit less than 2 USD (at that time) and took more than 7 hours for the first confirm. It was not as bad as those "$25 dollars txs" that so many people were complaining about, but it was not that good either... In contrast, Litecoin transactions cost a few cents and you get the first confirm in a couple of minutes. This is not to say that Litecoin is a better long term investment than Bitcoin, but if one had to pay for anything during a mempool crisis, Litecoin would be a better choice economically and practically speaking. So maybe part of the LTC rally we saw last year was simply due to this.

I believe once SegWit and LN finally get implemented and deployed everywhere, things will improve and maybe even be like in the "old" days for a few years at least. Not everyone shares this optimistic vision, but even if you do, you have to understand that if Bitcoin is extremely successful (i.e. massive global adoption) then tx volume will keep growing indefinitely, and of course fees will follow, meaning that on-chain txs won't be super common for ordinary people. We may see then a zoo of altcoins (in the same way today we have a zoo of gift cards, credit cards and state currencies) being used for different purposes and being traded using cross-chain atomic swaps.