If you understood markets regulated strictly by consumption i.e. free markets you'd know that if there is no barrier to entry ... and there are huge profits to be had it is impossible to arrive at a monopoly service provider
I'd love to learn. How about an example?
Basically everything almost everyone can do.
Opening a bar / cafe / restaurant / online shop.
No monopolies there. Some big players (MC Donalds, Starbucks, Amazon etc.) yes. But only because they are more efficient (cheaper). As soon as they try to exploit this position to increase their profits, new big players would step in.
And you can see this companies are really trying hard to build artificial barriers to make competition harder, but haven't succeeded yet.
An example where there is some success with artificial Barriers are ERP systems for companies, though.
Basically it would be possible for a decent programmer with some business skills to make such a program and the possible profits are enormous, but the big players (Microsoft, SAP, etc.) are working together to make their products more compatible across their platforms to make new competition harder.
Well with mining there is no better, all miner deliver the same quality so a monopoly is out of the question. And if more profits are to be had in mining more miners, small and big will eventually come online.
If we are to regress to a similar example, Apple is well known for having the most flexible, adaptive, highest capacity and most cost efficient smartphone manufacturing capabilities. For the most part, much of this ability is attributed thanks to simply them being the biggest (now second biggest) player in the market. No factories would do the things they do for other smartphone manufacturers like they do for Apple, because
everybody wants to be part of Apple's business. The only player able to dethrone Apple happens to be another huge manufacturer with years of experience and
having in advance all the in-house capabilities to run such an operation (Samsung). No other competitor ever managed to just "come online". You and I cannot make smartphones - we won't even cover the initial capital investment because everyone is buying Apple and Samsung.
Apple has no production (to speak of) of its own. They are basically only doing design
(and I mean design not development) and software (and in some rage the end manufacturing).
Everything else is done by EMS providers.
And no one is doing business with apple because he
wants to be part of Apple's business. They are doing it because there is money to be made.
Also, the entry barrier to make phones is not very high. Apple hat a bit of a innovator advantage in this sector, but this is already crumbling.
The Hardware for a smartphone is not high tech anymore and Android as OS takes away the software advantage.
The rest that remains are artificial barriers (I-Tunes, App Store, Coolness Factor, Patent-Bullsh***). But these can be very efficient.