Each person has their own limit at which point they will say, "Nope, that's too high." But to think that they are going to arbitrarily continue to up the fee till they get to $500 or $1000 is excessive. Yes the government does like to creep up the cost of things once in a while, but they know there is a finite limit they can go to.
The government knows they can't raise a license to $500 or $1000 to own a $400-$1600 snake. It becomes too large a percentage of the total cost, and in some cases could become more than the cost of the animal. The only way they could justify a $1000 license fee would be if breeders were charging $10,000-$15,000 for a snake (like some of the Ball Python morphs people sell).
I will agree the government will try to get what they can out of a license fee, but they know there are realistic limits to how much you can charge for something before people will find an alternative.
That's why US Postage Stamps aren't $2.00 each, because then some private company would come up with an alternative, and the government would lose out on the revenue they are currently generating.
If interstate licenses went to $500 each, I think you would start seeing more breeders popping up in other states where there are none. If that was the case, then no license would be needed and breeders could actually charge a couple hundred more per animal than they do now, because it would still be cheaper than buying out of state, and none of the money goes to the government.
Higher profit margins will inspire more breeders, unfortunately there is no way to know if they will be as good as some of the other breeders already around today.
On another note, all in-state sales have to pay any applicable Sales Taxes to the state or local governments. In Arizona my local sales tax is 8.1%, so on a $500 snake I am paying $40.50 in taxes, so I'm already paying more in tax than the current $25 license fee I would need for an out-of-state purchase.
The local purchase saves me on shipping costs, but then again if I had to drive The Beast (my Ford Excursion) across state to pick my snake up from a "local" breeder, it might be cheaper to fly it in. 
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0 of 3 goals complete, but all in good time.
- Eastern Indigo
- Redtail Hawk
- Neopolitan Mastiff