You can add !g to a DDG search and it will pull from Google. I'd say the quality of DDG is slightly less than that of Google, but not so often that sometimes having to !g the search is an appreciable problem. I've heard people say that DDG just uses Bing, but I'm not entirely sure how true that is.

The general problem with all search engines is that the moving target of the search algorithm often doesn't move fast enough anymore, and there's so much data that you're virtually guaranteed to have an overwhelming amount of wildly off-topic results. SEO farming has significantly damaged the utility of search engines, too. Finding obscure material is difficult because keywords are swamped, and it's exacerbated by the fact that the overwhelming use of search engines is for common URL lookup or to replace whatever invariably godawful embedded search a website might have. It's mostly DNS for people rather than a tool to actually search the web.

Speaking of, why is embedded search so invariably godawful? It's really quite impressive how useless it usually is.

Embedded search in arbitrary web sites sucks because it's a hard problem. The naive solution is to put all text in a database table keyed by "page" and do a sql "like" query. Don't ever do this. Some db's have full text search nowadays. I've implemented "embedded" search a few times in the past and I used Lucene, which actually works pretty well.