If mining is a marginal industry then Bitcoin is, and always will be, marginal. 
Bitcoin Mining is just a subset of Bitcoin. Just because mining is marginal does not make the currency itself marginal.
Correct - also, mining isn't marginal - it's the core design... without miners there isn't a bitcoin network.
That being said - Everyone needs to just stop freaking out about ASICs. a single will make what a single makes, and a rig will make what a rig makes... You'll still be struggling for some percentage of the entire network. We need to start focusing on growing bitcoin as a network, instead of just profit taking.
Lets get those transactions fees high enough to replace the block reward entirely. Yes? Great...
If you mean: keep the fees low but increase the number of transactions, then I'm all for it. Let's see how bitcoin scales.