A 4KTV doesn't force anyone to buy a 4K TV now. It will be able to downscale to 1080p or 720p just fine. So anyone who feels as you imply, can simply wait until TV technology gets to whatever standard of 4K they need before they buy.
Anyone buying anWatch right now will probably need to replace it in 3 years. So we shouldn't buy
Watch? Anyone buying an iPhone right now will probably need to replace it in 3 years. So we shouldn't buy iPhone? And so on.
Why does such thinking only apply to this ONE thing... but not pretty much everything else that Apple makes?
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People tend to keep their TVs longer than they typically keep their smartphones, smartwatches, tablets, laptops, etc. That means their decision what to buy is even more critical when it comes to future compatibility. I usually keep my TVs 7-10 years. I never said people shouldn't buy the Apple Watch, next iPhone or anything else other than 4K TVs that are not compatible with 4K blu-ray players and/or lack anything else that will be the standard by this time next year. Sometimes as you know, it actually pays to wait.