Read the datasheet more carefully 
The 50k write limit is MIN, no MAX is specified. I know people that have had these sensors running for years without problem, so the MAX value is probably much higher.
Being the self proclaimed Sensors Guy - It might have been in one of my previous posts 
I tried to explain it in another post:
Or as stated in the datasheet:
To initiate a temperature measurement and A-to-D conversion, the master must issue a Convert T [44h] command. Following the conversion, the resulting thermal data is stored in the 2-byte temperature register in the scratchpad memory /.../
A separate command is then sent to the sensor asking it to reply with the value of its scratchpad. A quite sophisticated little sensor I think.