2003 Chevy Tahoe Check Engine/02 Sensor

Question. My check engine light has been on/off for about 2 years. The codes keep coming back as 02 Sensor related. I've replaced all 02 sensors over the last 2 years. Because I've recently failed Emissions and need to register my car I took the car to the Chevy Dealer. The code came back as P0131 & P0135. They replaced the sensor. I picked up the car Friday evening, drove home and Sat morning the Check Engine light is on again. Took it back to the dealer this morning and another code P0141 is showing up. This is another 02 sensor. Is it possible to drive 5 miles and another 02 sensor goes. And if the p0141 is bad why did it not show up on the initial diagnostic. Clearly this is becoming costly and I wonder if the machine used to pull the codes could be wrong or if the code provided by the machine is just merely an indicator of where the problem is as opposed to the actual code/sensor being the issue. Should the dealer go a step further in the diagnostic other than just reading the code and repairing/replacing what the code indicates. Please help! I don't have any other resources to address this issue. Thanks in advance