competitive might be the wrong word he chose to use, but if you don't continue to expand, eventually it becomes less profitable.
Of course you're right, but really, what's kept this train rolling so long is all the pump and dump scams. It's speculation, pure and simple. People out there looking to make a quick 200% ROI by buying Doge at .0000005 and sell at .000001 two days later.
If this were operating on fundamentals of mining for profit, break even would take 90+ days, if it ever happened. And that's because of exactly what you're saying. Just look at the combined hashing power increases in mining ALL Scrypt coins over the last 3-4 months, and imagine Litecoin were the only coin out there and that all that hashing power were applied to it. It would never be worth it for the miners. Break even would be at least 90 days from initial investment, and that's extremely optimistic.
But that's not reality. In reality, we have the coin of the week. And a significant portion of the mining power is diverted to it just on the basis that it's momentarily way more profitable than Litecoin. This brings mining profits back in line with the coins that "count", and the folks mining the coin of the week are making a buck too. Where does the money come from? Again, speculators. In any gig like this, there are a VERY few people that make a ton of cash (pump and dump investor whales), a moderate amount of people that do pretty well (miners), and a TON of people that take it in the rear (speculators). They're fueling the whole thing.
As long as crypto currency is a commodity and not a currency and exposure continues to grow through media coverage, we should be fine (not speaking of ASICs here). But hey, who knows.
Just my 2c