When Michelin originally left Formula in 2006, it almost felt as if they were forced out. The then FIA president, Max Mosley demanded that there had to be only one tyre supplier in Formula 1 and following the shocking farce of the 2005 US Grand Prix at Indianapolis, it was always going to be Bridgestone that had the sweet spot. What was clear about the 2005 season was that Michelin had easily mastered the rules of one set of tyres for an entire race (as it was for that season), whilst Bridgestone struggled badly with long term graining.
There is really very little point on Michelin being the sole tyre supplier for the sport - they are by their nature a competitive company and will be eager to display their wares against other entities. With Bridgestone having no other suppliers to compete against since the end of 2006, it would be interesting to see how much of the tyre regulations in recent years were drafted in order to keep reporters, commentators and fans alike talking about their product, because the current tyre regulations do very little to actually benefit the sport in any way. It should therefore be very interesting to see what other suppliers (if any) throw their hat into the ring.