A flight school instructor reported the C172 lost power during climb and they landed directly back on the runway resulting in a runway excursion.

Narrative

On the go during touch and goes I noticed the climb rate was nearly 0. There was a building ahead on the departure end of the runway. The aircraft showed 55 KIAS on the airspeed indicator ~20 feet up. I took controls and landed the airplane on the remainder of the runway (RWY XXR). The runway was shortened and the aircraft overran the end of the runway and into the grass. I knew this would happen and did not find a grass excursion to be dangerous; especially compared to a looming building; and I let the aircraft roll to a gentle; complete stop. Neither the aircraft; nor myself; nor the student were harmed. No airport equipment that I know of was struck.We waited in the airplane with avionics and the engine running. I knew the airplane was good to taxi off under its own power. However; we just waited. Tower and ground control coordinated with us over the radio. Before long; a foam truck and an airport ops vehicle came by to assess. As they exited their vehicles; I performed the SOP-based engine shutdown procedure and secured and exited the airplane. Airport ops debriefed and informed us the event had been cleared. Our ops were contacted by the airport personnel and myself. leading to them coming out with a tow truck to tow the aircraft back; as well as a safety manager.All personnel and the aircraft were returned to the ramp with no further incident. I cancelled my further activities. After a lengthy debrief with safety; I headed home for the rest of the day.I was well rested; hydrated; ate well; and was feeling good. My student appeared stressed and neglectful of the factors of the flight; which I feel may have contributed to his delayed actions and non recognition of factors. I had asked him multiple times if he was okay but declined to answer clearly; which was the norm of my commercial students that did their initial PPL (Private Pilot License) at Pt 61 schools. I did not like it nor did I agree that it was okay for this deviancy to be normalized; but my school wants output and made me take steps to please the students in past moments; where I believed they should not have been flying. I believe this wording has been challenged by my school and I made to believe I'm wrong or inexperienced.I fully believe some of my commercial students are not capable of flying airplanes by themselves and should listen to an instructor like me who can guide them and make them confident they are either wrong or need to do something about their safety attitude but that phraseology rubs people the wrong way.The business conflicts of my school have also caused issues even though it was not my fault and I was told by my assistant chief 'I get it; but we've got to do something.' I challenged the assertion and told him I could not operate in a way that was not permissible by the school and he; instead of validating/recognizing the system failure; conveyed to me that this was due to the political nature of circumstances faced by the school. Nothing more came of it.The attitude of safety reporting at my school revolves around checklist and SOP adherence; not around safety culture and normalization of deviance. People are so busy checking themselves to ensure they are not wrong or non-compliant; there is a fear-based attitude prevalent that inhibits real safety.