Even though you know "their existence is an old and well known fact" you felt the need to post it, but when others also mention it you feel the need to be sarcastic ... how logical
I posted these old news in reply to a posting which perpetuated the old "I won't get upgrades if Canon plays silly again" meme, and the sarcastic tone (stemming from the obvious contradiction between my praise for the other guy's invention paired with the links to already existing products implementing that very feature) was another futile attempt to put that meme to rest for good. Read tron's posting immediately before my first one in this thread and then mine to get the context.
Every single one of those lenses developed some issueor another with AF or OS/VC after upgrading to a new camera or firmware, they would suddenly start hunting for auto focusing on a subject or the image stabilization would take longer to be activated and/or drain the battery with the OS/VC on even when they were not being used ... were they useless? absolutely not, coz I could still get great images with every one of them (except the Rokinon T/S, which was just a sh!tty lens from the beginning) but the issues they developed were annoying. I am sure a visit to the the third party manufacturers service center will fix those issues, but (as mentioned earlier) where I live there is no service center for third party lens manufacturers
I admire your patience, but personally I would not invest big money in gear that is unsupported in my country. If Sigma/Tamron/whoever are unable or unwilling to provide adequate service for their equipment in your place, they don't deserve your money. Software upgrades aren't the only reason you need a service center.
1. Put it to rest and spend your money. Then if something breaks wait for the 3rd party companies to really change the firmware...
Funny thing is all the pros I see rarely have brand new gear with them. It's usually wannabe amateurs who need the latest and greatest the minute it hits the market, when it is sold at a premium and hasn't received thorough testing yet.
With a few months of patience you can save 20+% on camera bodies AND can use cheaper third party accessories.
3. I do not recall reading about other 3rd party manufacturers doing the same as Sigma...
- Metz flashes come with a USB connector for firmware upgrades. My first post in this thread links to the relevant page
- Sigma received the most heat during the last decade, because in 2003 (release of the 10D) a long list of lenses in their lineup could no longer be used on Canon's latest and greatest, and Sigma decided to throw their customers under the bus. They seemed to have learned their lesson lately and want to be seen not as cheap alternative but as viable and well reputed alternative. Since that Err99 debacle is still in people's minds, Sigma had to come up with a viable option for simple upgrades.