Try to look once first how many jobs you'll find with 500hr on type on B737. You'll need atleast 1500ht TT.
After the LT I will have racked up a total of 1000h. Have found a couple companies with those requirements.
No it doesnt,paying for 500 hours just proves you have money and the airline in question has sufficient training captains.
Now if you get the airline to keep you in for a few years,then the next airline may believe you are up to the job.
Even if there are no guarantees for further employment there is still a chance. More than you can say about trucking on as usual.