The Charlie Brown specials moved to ABC over a decade ago, shortly after the passing of Charles Schulz. ABC simply outbid CBS and it was a smart move, since the Charlie Brown programs still win their timeslots, and score well among the desired demographic (25-54 year-olds).
When ABC won the rights to Charlie Brown, an unnamed CBS exec complained to the press, “after 35 years, you’d think they’d show a little loyalty.” Obviously, the exec wasn’t working at CBS back in ‘65, but it’s ironic that the network complained about losing the shows after they aired the first one only because they had nothing else (in terms of a Christmas special) to put in that time slot.
Remember when they had the “Peanuts” specials on, the usual sponsor was “Peter/Paul” candy which later became “Peter/Paul/Cadbury.”