I think you are being short sighted on what can be constituted as actual hardware upgrades in regards to a gaming console. Actual improvements such as making the CPU / GPU die smaller to reduce heat and power consumption, adding heatsinks or better quality fans to improving cooling. These ARE hardware improvements that convert to the purpose of increasing longevity and reliability.
Do I need to remind you how many different revisions there was to the Xbox 360 chipset be it Xenon, Falcon, Jasper, etc.
Upgrading the Hardware does not always mean making it faster or adding more clock cycles to the CPU, especially in regards to a console. Many game consoles get hardware revisions without changing compatibility with software, It happened with the PS2, It happened with the PSOne, hell it even happened with the original NES back in 1994 - http://en.wikipedia.org/wiki/Nintendo_Entertainment_System_%28Model_NES-101%29
And many others - http://www.digitalspy.com/gaming/news/a395003/a-history-of-console-revisions-psone-gba-sp-ds-lite-more-gallery.html
As example with this breakdown there seems to be very little change for the remodel to make a substantial impact regards of buying a PS3 Super Slim over the standard Slim. In fact with evidence of potentially cheaper / flimsier construction such as the sliding door for the optical drive.
This is clearly a case of hardware revision not for the sake of improvement, but revision for the sake to sucker consumers who don't know any better and always assume newer equates to better.
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