Duplicate content in search results -- still not detected

[EarWig]

Despite all their "advanced technology" and "attempts" to stamp out spam in their serps, in the areas I have watched over the last few years the same spamming techniques show the top ten results for geo targetted "widget widget" searches as follows:

No 1 Doorway/Duplicate pages
No 2 Doorway/Duplicate Pages
No 3 Doorway/Duplicate Pages
No 4 On topic result
No 5 Doorway/Duplicate pages
No 6 Doorway/Duplicate pages
No 7 Local Business Directory - on topic
No 8 Local University - on topic
No 9 Doorway/Duplicate pages
No 10 Local Directory - on topic

The only changes I have witnessed over the last 5 years are the same companies switching places in the top 20 results.

Techniques including multiple cross linking and invisible 1x1 pixel links predominate.
IMO this is something they can never gain control over without human intervention.