To me, paying no attention at all to the grand tours is like paying no attention at all to World Cup ski racing. Are there people in whose lives cycling plays a major part, who never look at what's going on in the Tdf? Sure. Are there people in whose lives skiing plays a major part who never pay attention to ski racing? Sure.
But think about what Bob Barnes and others say about what it means to advance toward a high level of accomplishment in your sport. It means that you're exploring and appreciating more and more facets of the activity - even those that might not attract you immediately or be comfortable for you. My observation about myself and others in both cycling and skiing is that sooner or later you start to pay attention to racing. You watch because you want to see what it's all about, what you can learn from it, and - mostly - because some of the performances inspire you and help you understand what the real benchmarks are. They're humbling in a paradoxically energizing way. Riding a century seems like a big achievement, and it is. You should feel good about it. If you do that, you're already probably in the 98th percentile of fitness and determination, among the general public, or something like that. When you then consider that riders on the tour are riding much farther than that, almost every day for most of a month, at race pace, over the Alps and the Pyrenees ... well, you realize how much more room for expansion there is in your own riding.
So yes, I'm going to be watching the tour. My spouse, strangely, because she is not a cyclist, loves watching it, so during July we really look forward to the nightly tour fest. (When I walk through the house in my bibs before a ride, my family mocks me. It occurs to me just now that when we're watching the tour, by contrast, the wife never takes potshots at Tyler Farrar's lycra. Hmmm.)