For a hardfork (like increasing the block size limit), which is changing the rules that all full nodes already validate, you need to get those full node to agree with the upgrade, or they will not accept the change. Whether miners agree with that is not specifically relevant: the network will ignore the old miners anyway.
Yeah, but the value of the money and the control over the protocol is in the scarce hash values of the blocks - not in the version of a software run on full nodes.
Whether miners agree with that is not specifically relevant: the network will ignore the old miners anyway.
One way of looking at it is saying that it's the network deciding which rules they believe the system should enforce (by choosing to run software that implements those rules). Miners are just clients to the network, who create blocks satisfying the rules the network wants, and are paid for that. Miners can choose to enforce stricter rules than what is demanded by the network, however.
OK - then please define "the network".
One could get an impression that what you mean by "the network" is just nothing - some network of peers, connected by a TCP protocol, that have no economical means of existence whatsoever. The thing is that the economical part, the blockchain, the currency itself - this is run by the miners, not by some network of peers.
The TCP network is just an interface to and from the miners, so people could do the transactions by the rules set and guarded by the miners.
That's the whole point: we (the users of the currency) are just the clients to the miners.
In reality, "the network" is simply the majority of the miners - at least for me.
You disconnect your mining-minority network from the miners - they will create their own. And you know it - in fact, no better person to know it than you.
You even know that they don't need to create any new network, as they would just keep going with their own fork, using just the same network...
Or to better highlight the "problem" (it's actually a security feature, rather than a problem), let me ask you a question:
Would you accept a bitcoin payment from me, that appeared only on a branch supported by a minority of the miners, as there had been a fork, because "your network" (the one that got my transaction) refused to adapt its software the the miners' other rules?