What were the problems of modern society, according to Henry David Thoreau in Walden, and why did he believe simplicity was the solution?

Thoreau says, in
part,

The mass of men lead lives of quiet desperation.
What is called resignation is confirmed desperation. From the desperate city you go into the
desperate country, and have to console yourself with the bravery of minks and muskrats. A
stereotyped but unconscious despair is concealed even under what are called the games and
amusements of mankind.

He believes that people have
become overwhelmed by their possessions, that they feel they must work and work more in order to
buy more and more stuff. They have houses that are too big, with rooms they don't need, and they
fill those rooms with things they don't need. The more people feel compelled by
materialist...