You can't, you can only get a 5 year license if you're on a non immigrant visa. And you can only get an IDP on a 5 year license. It's the same for thais and foreigners, there's no work around.
The cash requirement was never removed and has been around since the 90s/early 2000s (it used to be 10k). In reality, it's the most commonly used criteria to deny entry.