If the US gov would put some weight behind it, the US could easily catch up.
My SEPA transfer to a UK account always takes 2-3 days according to the service provider (can't vouch for that, maybe it's the provider who's slow but they are a small IT company so ...).
(I think Finland is +0. Germany and France probably not, for various cultural differences ️)
Once I tested that I was able to do a zero day transfer from a German bank to the Netherlands and then to another German bank. The same without the Dutch intermediary was a day slower.
The fact that there is an arbitrary money amount shows it's more of a fraud cutoff than a real limit.
In the mean time the credit on your account is debited a 'float' account that accumulates any debt to other banks or third party payment system. Each fast payment system also typically have a reserved amount deposited as a guarantee in the event that a bank runs out of money.
It's a real cost to reserve money so there is a restriction on the sums.
Can the central banks speed up the settlement? Yes probably, but it's a lot of work to do.
Bitcoin blocks will always be ~10 minutes, if you pay the fee to get into the next block, it'll be 10 minutes until your payment is confirmed, before that, all the nodes will announce it anyway so 0 conf is much faster.
On top of that, if you want to pay less than a certain transaction fee (right now it's $1.62) you probably won't get into the next block, see https://bitcoinfees.github.io. Recall that 1 block = 20 minutes and add that on top of the confirmation time.
 https://blockchain.info/block/0000000000000000005f0e639f66af... look at the Timestamps of this block and the Previous Block
 https://bitcoin.org/bitcoin.pdf page 8
 https://bitcoinfees.21.co/ (a satoshi is 0.00000001 BTC, 10,000 satoshi is 40 cents right now)
Users don't want to play a complicated expensive, impossible to win game in order to get their payments processed in a known timeframe.