You are spot on. I watched this happen to Skinny Water, a competitor to CELH that eventually went under. They lacked an angel investor like Carl.
There is of course always the possibility that a large company will come along and buy up CELH (though I doubt it would be at much, if any premium to the current market cap), but the odds are long.
They have enough cash to keep buying growth for another few years, but the problem is that increased sales requires increased SG&A and even when you stop buying sales, that higher SG&A number rarely drops much.
Gross margin is also a difficult number to hang your hat on because in most cases, co-op advertising, slotting fees, etc. end up in SG&A, which makes gross margins look higher than they actually are.
How long until investors tire of waiting for profits that seem to be further and further away is anybody's guess. They've been patient so far, but that's largely due to the massive holdings by a few investors. But with a P/S ratio over 7 (TTM), it's hard to see this moving up over the long haul.