F1 Fastest Line throughout the years

[xcutionr13]

I noticed that previous on the previous years (2008 and older), F1 drivers prefer to take a much tighter line through a corner.

Example in Shanghai International Circuit in Turn 1 and 2 drivers took a much tighter line.
https://www.youtube.com/watch?v=NCQBIUUiHsI - 2004 V10 Groove tyres with traction control
https://www.youtube.com/watch?v=Erx4y28xOx0 - 2005 V10 Groove tyres with traction control
http://www.dailymotion.com/video/x8lgf1 ... jarno_auto - 2008 V8 Groove tyres without traction control
https://www.youtube.com/watch?v=KI-bhFYl7C4 2010 V8 Bridgestone slick tyres, double diffuser
https://www.youtube.com/watch?v=WBqqIzBcjUk 2015 v6 Pirelli Soft compound

Different circuit Spa-Francorchamps look at Bruxelles corner
https://www.youtube.com/watch?v=V5Qy6cOua2I - 2005 V10 Groove tyres with traction control
https://www.youtube.com/watch?v=JFP6Bzlk5Z8 - 2008 V8 Groove tyres without traction control
https://www.youtube.com/watch?v=09-DoDmP6ro - 2009 V8 Bridge stone slick tyres double diffuser
https://www.youtube.com/watch?v=aTkbgLKa65Y - 2015 v6 Pirelli Soft compound

Different circuit Hungaroring look at Turn 2 and Turn 14.
https://www.youtube.com/watch?v=leG01_S9Mmg - 2005 V10 Groove tyres with traction control
https://www.youtube.com/watch?v=NWNCUwZsMaI - 2007 (w/ traction control) / 2008 (w/o control) V8 Groove tyres
https://www.youtube.com/watch?v=clzMedymn6M - 2009 V8 Bridge stone slick tyres double diffuser
https://www.youtube.com/watch?v=7MGXeW6aeT4 - 2010 V8 Bridge stone slick tyres double diffuser
https://www.youtube.com/watch?v=g61h6MI_02s - 2014 v6 Pirelli Soft compound

Summary: I don't think it has to do with traction control as up to 2008 drivers are still taking much tighter line. Tyre durability is also not the main reason as drivers are still not taking as tight line as 2008 and older even with Bridgestone slick tyres and double diffuser in 2009-2010.