No, not infinitely divisible but to destroy every single BitCoin would be like trying to count every atom in this planet, the number is so high that you would have to destroy every BitCoin simultaneously because a single Bit Coin can still be divided another 1 million times if need be.
That still is a pretty hard limit. I would even go so far as to say "famous last words" as the folks who came up with IPv4 had to deal with the exhaustion of the address space (about 4 billion IP addresses). Unfortunately the current demand world-wide is about 15-20 billion at the moment, and no end in sight about how many more may eventually be needed, hence IPv6.
Back elsewhen nobody thought that there could ever be any exhaustion of the IPv4 address space as the total number of computers that could ever conceivably be put onto a computer network was in the 100k range. Gordon Moore famously made a joke about how microprocessors would become common to the point where a typical high-end hotel would have at least one microprocessor for every doorknob in the hotel. He didn't expect to see that actually happen about 15 years later when quite literally every doorknob in the hotel he gave that address in put in microprocessors... for security purposes.
I really don't know how far and wide that bitcoins will go, but limiting them to just 1 million or even a trillion may seem in the long run as something of a major shortcoming. We'll see on this issue if enough "space" has been set aside to deal with all eventualities that could happen to bitcoins.
Then again, that would be a wonderful problem to have to address, at which time there would be a major international conference involving major heads of state or at least ministerial level representatives (something like the Secretary of State from the USA) who would be debating about the future of Bitcoins and how to "resolve" that problem if it was a serious issue. I think a "reasonable" technical solution could also be found if that was a problem and is certainly not something to worry about at the moment. Certainly anything needed for the next couple of decades, if bitcoins even survive that long, can be accommodated with the current system.
