It has not changed, the problem is that the normal narrative has the causality wrong.
The explanation we get is this: private banks have a quantity of reserves and they can lend only what the money multiplier allows them. So, they are limited by the quantity of reserves they have. If that were true, they would be limited by the quantity of savings in the system.
But in reality it works the other way around. Banks lend first (hopefully only when makes business sense to lend) and then they search for reserves.
A bank lend (creating money in the process) and, after the fact, if it doesn't have enough reserves already, it tries to get the reserves from other banks (inter-bank market). This is a legal requirement, so, they have to get those reserves.
This creates an offer-demand dynamic between banks that move the interest rate up or down.
If the quantity of reserves was fixed, that would be the end of it, but, because Central Banks have a target interest rate that they want to keep (but not a money quantity target), they have to accommodate the quantity or reserves in the system reacting to the inter-bank market dynamics. Adding or retiring reserves as necessary to keep the interest rate that they want.
The central banks control the interest rate, but that means they can't control the quantity of money in the system. The quantity of money is determined by the demand of credit from the economy (and not by the available savings).
If we understand this, we see that private banks are not limited by savings in their lending capacity, they are limited by how many business or households are requesting credit (and if those request make business sense for the bank).
This is a good reading about those subjects:
https://www.bankofengland.co.uk/-/media/boe/files/quarterly-...