In the nearly 30 years between the launch of the Fairchild Channel F and the Microsoft Xbox 360, console owners didn't have to worry about hardware compatibility issues. You bought a system, looked for the name of your system on the software box, and hoped that the manufacturer would support the system long enough to justify your purchase.
There have been a few re-designs along the way, almost all of which resulted in a smaller (i.e. cheaper to manufacture) console such as the Atari 2600jr, the top-loading NES, the Genesis 3, the PS One and the slimline PS2. While there were a few software issues, for the most part none of these re-designs fundamentally changed the system's architecture.
Not so with the latest generation of consoles, which now include multiple SKUs from both Microsoft and Sony...
As long as hardware manufacturers continue to add expensive new technology to their consoles, and remove it in an attempt to re-position themselves in the market, the recent phenomena of multiple SKUs is likely to continue.