[carpetmojo]

Not at the start, perhaps.

But the whole point of achieving a monopoly status, in anything, is that you are then the market, in effect, and can therefore dictate that market accordingly, as you, not any outside party, wish.
(Here the nasty ogre of political views or agendas that can also be inculcated, don't forget. Like, for example, a strong right or left leaning media and its influence.....)
Of course a minnow may always be "allowed" freedom to start up, and make profit/achieve some success - but wholly at the choice of the main monopoly presence.
But, start making too much profit, or become inconvenient in any way, and the monopoly will alter the market to either drive the minnow out of business, buy it out, or use any number of other tactics.
And, naturally, as said already, inevitably a "creative stifling" will occur - or more left-field activities ascribed to a "ghetto" to wither on the vine, or make enough of a success to in turn become mainstream.
Practically the only situation I can think of a monopoly being good for consumers or society, is the one of nationalisation of an industry - and that can also go completely belly-up !