Radiator problems of the 2013 Mini Cooper

I bought my Mini brand new in 2013. I took it to be serviced regularly at crevier Mini and I took it every time I had a service light come on, which was multiple times in the first couple years. The warranty lasted until June 2017. In November 2017, I noticed a musty smell coming from the air vents, and noticed liquid was leaking from my car. I towed my car to the dealership, and Mini techs found that my thermostat housing failed and leaked, and the head gasket was not properly sealed which caused my car to leak coolant. Mini USA helped with the cost of my repair to my car which only had 37,000 miles on it because of its low mileage, for which I was very grateful. Now, in August 2018, I noticed that the radiator fan which is directly connected to the thermostat was not turning (the fan was still functioning when connected to power). I took it to get serviced and Mini techs found that my engine had overheated to the point of being critically damaged. There was coolant found in the spark plugs which means most likely that the head gasket leaked. When I asked if this could have been related to the prior repair, I was told it is difficult to pinpoint the exact reason this happened. However, there should have been an indicator light to prevent this type of critical problem before it is irreversible and can't be fixed, but there was not. The entire engine has to be replaced for a service charge of around $7500. This is worth more than the car itself. What I learned is that even if you do everything right, by the book, and per recommendation from Mini, your car can still fail and die within 5 years- right after the company warranty wears off. This has shaken my faith with the Mini company. For no reason should a car have failed after being driven for around 40,000 miles while receiving service from the dealership itself.