I agree that google today isn't as good as it was a year ago, and that their search results are not *quite* as good as they were a year ago, but the search results are still better than DDG's. "Better" means that I get results that I deem to be more relevant to my queries. The words "I" and "my" are important there.
My real beef with google these days is their hijacking of the cursor keys so that they don't scroll the page any more, instead they select the next link on the page.
Were google's as good as google's when they started out?
They were better than altavista and made those of the various msyahaol 'portals' look positively primitive, but ignoring the valueless, quota-sucking and annoying web2.0 frills, their core competency did improve markedly with time, expertise and especially size in the early years.
For the last few, their value adds have been mostly valueless. Mostly change for the sake of change. Kinda like most of the additions MSOFFICE for the past 10.
Google's results were, at the point I started using it, mostly better than the competition, although I did still occasionally use Yahoo's "curated" index for a coupla years. If DDG is to get users, it needs to be as good as or better than the competition most of the time. The competition is Google. My apologies for typing "If only DDG's search results were as good as google's" instead of "If only DDG's search results were as good as their competitors'" which appears to have confused you.
ddg have their own index, and then defer to bing (yahoo also uses bing for results, so you could argue they are yahoo results)
what they do differently is to query lots of 'authoritive' sources to try and provide a good result without an index.
so if you search for 'perl fork', your first result will be linking you to 'fork' in perldoc.com
it also plugs in to wolfram alpha to provide answers to humanish queries like 'what is four times five', currency conversions etc.
so yeah, they have stitched together a *LOT* of third party apis (especially free ones) to bring you results. its the sort of approach that will polarise peoples opinions, with people going 'thats lame they are just using apis... boo!' and other people saying 'hay cool, thats a great - why hasnt someone done that before'
either way, since its a free website if you dont like it you can easily get a refund.