Interlagos was team co-founder Patrick Head's last Grand Prix in a Williams shirt.
The 65-year-old veteran handed over as technical director some years ago for a lead engineering role, and earlier this year cashed in millions of his team shareholding for the Frankfurt stock floatation.
He was wearing a team shirt at the weekend's Brazilian Grand Prix, but admitted that if he attends races in the future, he will be less conspicuous.
"Well, we've got new senior technical staff," said Head, referring to figures including former McLaren designer Mike Coughlan, who has succeeded Sam Michael as technical boss.
"When it came to the beginning of this year and found ourselves in pretty much the same position (as before) we had no alternative than to make some senior position changes," he explained.
We had no alternative than to make some senior position changes
"When I looked at it, I'm very confident in the new people and didn't really think there was a position I could seriously contribute.
"I'm going on to other things," he added, referring to Williams' KERS arm Hybrid Power.
Head told the BBC: "If I turn up to Grands Prix next year, I probably won't be wearing a Williams shirt."