Why is the gospel so often advertised as a religion that will make your life better?

I have been encouraged lately. I recently started listening to lectures from Hans Peter Royer, director of Tauernhof, a Torchbearers school.
Hans Peter reminded me, through this lecture, that the gospel is NOT meant to be a life IMPROVER, but instead, a life SAVER. The gospel does not promise to make our lives easier or happier, but it does promise to save us from death, give us hope of salvation.
A person will not hold onto Christ if when they accept Christ, they think they are going to gain a happier, more comfortable life. A person such as this will abandon the faith when they discover that life with Christ will not always be comfortable and will actually be hard and challenging at times.
In contrast, if an individual accepts Christ knowing that he or she NEEDS a Savior, they WILL hold onto their faith, because they know their life depends on it.

Wow.
My LIFE DEPENDS on it.