I checked Wookiepedia, and in the article about
Clone Troopers it says that they introduced non-Clone Stormtroopers because the clones were getting too old and they couldn't make more because the cloning facilities on Kamino had been shut down. The Kamino article doesn't say anything about why it was shut down.
Did Palpatine control Kamino?
Just finished season 3 of the clone wars (for the first time) and there's an episode where the Emperor tricks the senate into deregulating the banks, so that the senate could borrow more money to make more clones, and the banks could charge a higher level of interest on the loan.
This tells me a few things.
1. Chancellor Palpatine does not have full access to the treasury. They can still get him on fraud or corruption, if he tries to build his death star, or other selfish projects, he doesn't care to explain about to the little people.
2. Chancellor Palpatine directly or indirectly controls/owns the banks. The Senate and the Separatists are both borrowing money from him, and he's charging an exorbitant degree of interest to both halves of the galaxy.
3. Chancellor Palpatine directly or indirectly controls/owns Kamino. The Chancellor is gouging the senate, by selling them clones that they probably do not need, with money they borrowed off him.
4. Chancellor Palpatine directly or indirectly controls/owns the battle droid foundries, and he's charging the separatist (world')s through the nose, money that they are borrowing off him, to buy Battle droids that they really probably don't need.
##ck.
It's the Music Man?
So...
Once the Chancellor became Emperor, he didn't have to dick around, to take money from the Treasury, without bean counters getting up his ass, so Kamino and the foundries were closed down because they are redundant.