As matter of fact, there is a lot of innovation in fiat currencies. You might have noticed that the US merchants are switching (or have switched, they have a deadline in October) to the "Chip and Signature" method of authorizing cards. Some are experimenting with NFC payment methods. Going back, banks offered online access to everything and provided you with a number of one-time use card numbers. Going further back, online purchases became possible. It's quite a lot of innovation that happened within just last 20-25 years.
I cannot say much about all the alternative cryptocurrencies. If some are better, more power to them. However it is essential that a cryptocurrency that is selected for a major one in a country has to work at least as well as the existing systems. How long does it take today to authorize a card scan? A second or two at most. How long does it take to confirm a BTC purchase? Five to fifteen minutes. As you can see, BTC is simply not ready to become a viable payment instrument. By design, it never will be. I assert that the BTC is a good, interesting experiment that demonstrated something good and something bad. The blockchain was a significant invention - and it is also the Achilles' heel of the whole design. BTC is a heavyweight design with extremely high cost of each transaction. Compare to current banking systems - they are decentralized, they are scalable, and they have very low cost of transaction. The customer does not need a blockchain; he only needs his goods. The math of confirming the purchase is not his problem, it should stay between the merchant and the bank. It is too much to ask the whole planet to vote on my purchase of a cup of coffee.
A couple points of clarification:
1. BTC transactions are logged and propagated within seconds, not 5-15 minutes. There is a lot of confusion about this. The propagation rate of a bitcoin transaction through the network is a few seconds, at least as fast as a credit card purchase. And 0-confirmation technology is deployed now by processors like Bitpay that confirms the spend is valid with confidence. What you are talking about is the blockchain confirmation process which can take an hour or so to prevent double-spends. But this back-end process is comparable to the credit card settlement process involving chargebacks, which can extend out 3 months! As a merchant you will know you have your bitcoin from a customer long before you’ll have confidence your credit card transaction won’t be reversed.
2. Altcoins all have much faster confirmation times at any rate, and Bitcoin’s Lightning Network proposal will enable it to compete with them. Your claim that the blockchain is a weak point slowing things down compared to private trust-based fiat systems is thus erroneous. They are the slow ones, particularly when it comes to final settlement.
3. If concerned with the cost of mining/transacting bitcoin, go with Proof of Stake coins, rather than Proof of Work coins like bitcoin. Those do not rely on mining hashpower, so they may be a better option in the long run, based on market demand. Again, the innovation is out there, and claims that bitcoin/crypto are fatally flawed are wrong because the protocols can be updated many times faster than fiat systems.