It is not primarily Thunderbolt that that is killing off Firewire. It is USB 3.0 also.
Name a new camera that hit the market in the last 2-3 years with Firewire 800 on it? In the consumer/prosumer sprectrum I don't think there are any. You may be able to dig up a handful of niche cameras, but the overall trend with cameras as they have largely converted to "file storage" devices ( they have drives and transfer is a file transfer problem) is to dump FW.
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etc .
You make a lot of valid points, but you don't consider one thing : any computer, OS and such that is being used in the professional world needs to maintain backwards compatibility a lot longer than anything that is made for the consumer market .
It's always easy to be in favour of changes when you have no dog in the fight .
FW is on the way out, which is unfortunate in my opinion, as I think it's the cat's meow re. file transfer and usability, but such is life .
Ethernet is a pain, yet again, life ain't perfect - many people still depend on it, and dodgy adapters don't always get the job done .
TB isn't there yet to allow for a seemless transition, and USB has never been very flexible .
It's way too early for an MBP without FW , but that's just me I guess .