No, it's not forever. It is quite possible to hit it within 20,000 free rolls, but supposing you make 10 free rolls per day on average, it will take 2,000 days or from 5 to 6 years. Of course it might look stupid to work for 5-6 years in order to have a chance to win $200, but visiting the site from time to time is not exactly a work. It's not so hard to do especially if there's no captcha to solve, and also don't forget that you always have a chance to win it right away.
There is no way to hit that waiting for that long time, I think it is much more easier if you combine it with some few rolls then you do not need to wait for that long, a few rolls each day will really help you out but the problem is if their games and freerolls have coresspond to the roll number or not, if they connect each other then it might do
If you mean to ask whether you will win $200 by rolling 1000 in the "Multiply your bitcoins" section then the answer is no, you will not. And that's understandable because the site would go bankrupt if they were giving away that much. Theoretically you can win $200 in that section, but only buy placing a corresponding bet with a corresponding multiplier like on any other dice betting site.
Yes you will win it someday after you pass your 20k rolls then it might later be popped out, or may be it will be in the middle of 20k rolls, we never know or predict when it will pop out since this is all is just based on some calculations here. If you do some freerolls here I think you can get it in no time here, if you can do 1k rolls each day, then you only need 20 days to hit it if only freerolls and hi-lo games has the same output