There's some telephone game being played here.

The three year number was a surprisingly low figure sourced to some anonymous Google engineer. Most people were assuming at least 5 years and maybe more. BUT, Google then went on record to deny that the three year figure was accurate. They could have just ignored it, so it seems likely that three years is too low.

Now I read 1-3 years? Where did one year come from?

GPU lifespan is I suspect also affected by whether it's used for training or inference. Inference loads can be made very smooth and don't experience the kind of massive power drops and spikes that training can generate.