The result? The 2006 Democrats (sans the most conservative members) barely won the chamber. You can vary the exact details of the 2018 calculation (e.g. calculate win rates for districts with leans that are within two points, three points, 1 ½ points, etc. of each other), but Democrats typically won around 220 seats — just a couple more than needed to retake the House.
Performing the same procedure with 2008 results (applying win rates and eliminating Democratic wins in highly conservative districts), Democrats perform better, getting close to or above 230 seats, depending on how the calculation is tweaked. This makes sense — some of Democrats’ gains between 2006 and 2008 were in the ideological “center” of the map, and Democrats won the House popular vote by a larger margin in 2008 than 2006.
These numbers clarify what a “2010 strategy with 2006 numbers” actually means. If Democrats can keep their safe districts and drive up their win rate in swing-to-right-leaning districts, they may be in a position to take back the chamber.