Monopolies are like monarchies. There may be a good one now and then but the system itself is faulty and prone to badness. A good monopoly will generally turn into a bad monopoly over time, because there are no competitive forces keeping it honest. Though there are rare exceptions. A competitive market tends to be long-term stable, resulting in better sustained, long-term results for customers.

Google is very dominant but nothing it does could really be considered a monopoly, even search. Very few google products have significant "lock-in" the way most monopolistic products do.