This is my 3rd go at long-term sobriety (6, 7 and now 3.5 years), and each time it has been a big deal. The 2 times I relapsed (once for a year and once for 8 years) both were preceded by periods where my sobriety seemed to become less of a big deal to me. So my experience is that there seems to be a direct correlation between the significance I place on my sobriety and my ability to maintain it.
I believe that if I was able to just quit drinking and move on with life never to worry about it again, there would be a reasonable chance that I didn't suffer from alcoholism. The fact that I was able to go for years without drinking only to have it come back and wreak havoc in my life over and over is enough proof to me that sobriety will always be a big deal to me.