I was so disappointed with McLaren for not turning up with KERS. What is this a gentlmens club.
See MSC and many other people/teams on what you need to do do to be great. Sod verbal agreements.
I think back then remaining part of FOTA was quite important to Mclaren. They were in the midst of massive budget and other discussions with FOM and the FIA. Dropping out of FOTA just to run KERS would have been quite damaging.
Now though, as Ferrari say, FOTA has sort of run its course. So jumping ship at the sacrifice of some gentleman's agreements is less of an issue.
It will be interesting to see how the Concorde agreement discussions go this year as a few of the big teams (Ferrari and RBR) will be very much fighting their own corners by not being in FOTA. I wonder if Bernie will try and play them off against each other ?