Why would someone take on restrictions, that effect everything they eat and their daily schedule in life? The answers you have gotten are good and actually are from mostly those who have chosen not to make that path (or have left it.)
I can give the point of view of having don’t exactly like that. But first, the following is a chart created by the Pew report projecting the future:
The chart shows that in spite of Reform and Conservative Jews as the largest groups, we can see by the chart their future is not promising. The more they bend the rules, distance themselves from any dogma, decrees or discipline; the fewer people feel a need to be part of them. If you are not promising any future or making any demands, and essentially have no belief that is different from any other group – why should anyone bother calling themselves a Jew?
Yet, if one is coming from the background where nothing is expected of them, it is a tremendous leap to suddenly ‘inflict’ oneself with rules. Though do we look at athletes, artists, or anyone in a demanding profession that they are acting a bit psychotic because they are making their lives so difficult just to be an Olympic runner, a top dancer, a scientist or doctor? If someone wants something that is meaningful it usually means there is discipline, sacrifices, and rules to follow.
Judaism is no different. If you want to benefit from the beautiful family life of having children that follow your beliefs and live their lives in admiration and wish to continue a 3000-year tradition, one actually has to live that life and recognize all its beauty even in the difficulties.
Believe me keeping kosher and keeping Shabbos very soon is not a burden, but a pleasure. (Besides, there are so many other things to keep learning and accepting.) When you start to see the beauty in the system and the amazing world G-d gave us especially in his rules and demands; it is not difficult, only opportunities.
I think if you would ask a dancer, a doctor, a football player; how could you give up so many hours a day to practice either the sport, the profession? how could they have given up the years that they needed to invest to get where they are? Do you think they would say it was not worth it? Even more so; to live a life that is commanded by G-d and see one’s children and grandchildren live by the same beauty – it is what we call – naches – true pleasure.