I think you have the Bitcoin pizza story mixed up. Laszlo did not exchange $10,000 worth of Bitcoin for pizza instead he exchanged 10,000 Bitcoins for the pizza. At the time the 10,000 Bitcoin wasn’t even worth up to $50. You can check the post here:
https://bitcointalk.org/index.php?topic=137.0. Also, I don’t think that the person who got the 10,000 Bitcoin still has it. It’s possible but the chances are really slim because Bitcoin merely being $1000, that’s a lot of money that the average person may want to have cashed out.
There is many accounts which hold a big amount of Bitcoin on it. Some of these accounts have an owner which died, lost the keys to open it, holding for a better price, companies using it to avoid taxes and so on.
Laszlo spent a big amount of Bitcoin for something that worth it at that time and which doesn't worth it anymore. I would buy a normal pizza right now for 0.00045 Bitcoin which is equivalent to ~$20 but I will definitely cry it next years when I see that I bought a pizza for ~$200 or even more.