The devices that are light used fail sooner than the one that is well used and overused.
Your low page count in 3 years could be one of the printheads fail reasons if you have been printing for 1300 pages monthly your page count would be closer to 50k pages. The one with 70 602 pages you mentioned was used every day if it was used for 3 years that makes close to 2000 pages monthly and it's still working.