Dealing with a monopoly is an entrely voluntary activity. There are always
substitutes for what a monopoly sells. Monopoly profits attract entry,
leading to competition. Only government enforced barriers to entry prop up
monopolies. Otherwise they quickly fade. But the prospect of initial
monopoly profits drives innovation leading to research, new products, and new
services. A perfect monopoly (prefectly price discriminating) produces an
economically efficient output and uses resources in an optimal way identical
to perfect competition. Modern monopolies are widely held by stockholders,
including institutions like pension funds, so monopoly profits are shared
society-wide. For most things, unconstrained monopolies would be preferable
to unconstrained governments, maybe even national defense, which can be
supplied by large aggregations of capital, and the protective effect priced
into their goods and services.