Yes, users can make the difference over miners.
Because, miners generate blocks ... but it's the users (software) that it actually "accept" the block.
If miners want activate Segwit with an other method, regular users don't see this method.
That's why, only this graph is valuable for the 89 000 nodes of the Bitcoin network :
http://bitcoin.sipa.be/versions.htmlIf 800 miners want use an other software, they can.
they fork.
simple.
But it will not be Bitcoin network.
Not the 89 000 nodes that they wait Segwit and 1Mb block.
And, just an hint : BIP148 enforced client are 2700 nodes, now ... more than all "others" miners.
You can't build a network without nodes.
And only 4,3% of the WHOLE Bitcoin network prune the local blockchain.
That's why user (node) can make the difference.