Sorry to hear you lost your purse.

If you left your purse in the taxi, one reason you might not have gotten it back is because the taxi driver didn't find it, but the next person who got into the taxi did and simply took it.

I worked with a woman whose husband drove a taxi and she told me they would find cameras and wallets and airline tickets and all sorts of things left behind - she said her husband and other drivers were very good about trying to track down the owner, or else would give the item(s) to the main depot and they would try to track down the owner.

Consider yourself lucky - when I was living in Europe I met a young couple who had flown into Paris and then took the subway. Only after they got to the hotel did the girl discover she had left her camera case in the subway - but in the camera case, she had stored their passports, return trip tickets, all their cash, credit cards, hotel vouchers, Eurail passes and her list of phone numbers and addresses. Now THAT was a disaster...