Not really a bad idea from Intel... both them and customer can have some benefice from it...
Let see a usual situation... a processor with 2 core at 20$, a other with 4 core at 40$, a other with 6 core at 60$ and a other with 8 core 80$...
First, at the fabrication level, it is more expensive for Intel... yes, it is more cheap to build a lot of identical thing that a few of each different thing... method will allow huge mass production with lower price...
At the customer level... you first buy by example the 2 core... with time, software/game ask more power and you buy a new processor with 4 cores... trowing the old 2 core to trash because nobody wish it ( too slow, too old , etc )... later, time for a 6 core... and later again, the 8 core... In total, you will have spend 20+40+60+80= 200$...
Let say that Intel build a single processor with 8 core but only two enabled and sell it at 25$, and ask 25$ for each 2 cores upgrade... a rip-oof, you will say... the basic 2 core version is more expensive... but again, you are wrong... it is a little more high price for compensate the loose of income for intel... mass production compensate for one part but not all... and the customer in all this ? it is simple : 25$ for the first 2 core activated, each upgrade at 25$ : 4x25= 100$ ... yes, with full upgrade, you have spare 50% when related to the first case up...
At a other level, the system can be interesting too... ecology level... need to build only one processor, it mean that 3 processor are not trow in the nature...
A other thing who can be interesting, only pay for what you need... you encode/decode a lot of HD film, simply enable the part of the processor who speed up the process... you make a lot of high quality render, simply enable the part of the processor with a high speed hardware render engine...
In fact, it can be fully beneficial for the customer, the only danger will be for Intel... it will not be long before hacker/pirate create some piece of software who generate a key for unlock the extra feature of the processor... buy the 25$ 2 core version, torrent, generate key, unlock feature and you have the 8 core version for almost nothing...
Except that with time, the processor get outdated quickly and thus its price. And you can trade in back your old hardware.
Take your example, after one or two years the customer decide that the 2 core is obsolete and would directly upgrade the processor to 8 core thus he will only have to pay $20 + $80 = $100. And by them the 8 core may cost only $40 thus $20 + $40 = $60. The customer may even trade in, sell the old processor for $5 so the total cost will be $55 instead of $100.
Yes this is just an example and the price may differ so to upgrade the hardware may be not so costly, however think, with your experience how long will you upgrade your processor, half a year? 2 year? By that time now technology will come out e.g. 16 core processor and making the 8 core upgrade less attractive or the 8 core become so cheap that directly buying it is more worthwhile.
