Unfortunatly with most gymnosperms (piney type trees) regrowth at the base of a tree is not really an option. Once the area becomes shaded it isn't going to grow back. If there is ample sunlight a higher branch can and will grow, and as it becomes heavier it might reach the ground. It is paramount to understand that if you prune past the green portion of a gymnosperm it is not going to bud and start growing in the brown.
As for the
Roots go everywhere because in times of drought, the roots seek out water, and that's where your sewer pipe comes in.
It's true roots grow to water is, but they won't just randomly attack sewer pipes. the pipe has to already be leaking. I read the studies done on it when I was in college earning my Urban Forestry Degree, please don't ask me the document the research as it has been probably 10 years since I read the study. The problem isn't the tree, it is the leaky sewerpipe.
If it is a city street tree, it is probably property of the city. If it is within 13 feet of the road (the city right of way), and it looks like the whole neighborhood has the same tree it sounds like it is the cities tree. You can call them and have the city forester check it out, and get thier guidelines for pruning, and/or removal. It is going to depend on the city or township. It could be illegal for you to just remove the tree.
Water can help on losing needles, and sun. In periods of drought trees are going to drop leaves (needles) to survive. And without sun the needles are going to drop, as the leaves will not be viable.
If you want to keep the tree (A tough choice, but how soon will you get another tree as large) you could try and plant a bed underneath it, but know that the soil conditions are going to be more acidic then the rest of the yard because of the needles decomposing, so the plant will have to tolerate low light, and acidic soils, or mulch (that seems to be the answer around the world currently).