All these articles talking gloom & doom about the ratings are full of it. DWTS has always skewed older in its ratings. Some other show will often beat it for the 18-34 or 18-49 demo, which industry people hype as the key number. But in terms of total viewers, DWTS usually has up to twice as many viewers as the nearest competitor.
ABC will still get some very nice ad rates from these numbers. DWTS has nothing to worry about.