If you want to see your lottery works:
1. Use an escrow for the first time draw.
2. Use a provably fair system for the drawing
3. Reduce the ticket numbers and ticket price, no need to offer such big prize but it needs to take so long time to do the draw.
4. Use a fixed time duration for the lottery, lets say weekly or monthly. Then do draw no matter how many tickets sold.
5. Take small percent of the prizepool only.

If you keep the way as what you want with 100k tickets and wont draw till all tickets sold, there will no draws happen till the end of your site.
Of course it is just suggestion, take it or leave it.