Well, I thought my comments did answer your question.
- the fact that this signature works today (and I am not convinced it is actually so unique and stable to be really useful, again you don't have flash or java on iOS nor can you really customize the browser, so you will have lots of collisions) doesn't mean it will forever, for instance flash, java and silverlight are on their way out of the browser. And the more plugins and fonts you have, the more unique your signature is, the more likely it will change as a result of updating something (typically at least once a month) and therefore the less likely it will be useful to tracking you (your identity changes regularly).
- the fact that there is a flaw already doesn't mean we should introduce another one.
- IP protocol is evolving much more slowly than browsers and therefore a flaw in the IP protocol is a lot more problematic than a flaw in a current version of the browser.
If you're not convinced that browser fingerprinting is a useful tool in an advertiser's tracking toolkit, then you need to read what the EFF, lcamtuf, and other security researchers have to say. Or, you could just go work for a grey or black-hat internet advertiser.
- the fact that this signature works today (and I am not convinced it is actually so unique and stable to be really useful, again you don't have flash or java on iOS nor can you really customize the browser, so you will have lots of collisions) doesn't mean it will forever, for instance flash, java and silverlight are on their way out of the browser. And the more plugins and fonts you have, the more unique your signature is, the more likely it will change as a result of updating something (typically at least once a month) and therefore the less likely it will be useful to tracking you (your identity changes regularly).
- the fact that there is a flaw already doesn't mean we should introduce another one.
- IP protocol is evolving much more slowly than browsers and therefore a flaw in the IP protocol is a lot more problematic than a flaw in a current version of the browser.