Most gamers don't want the hassle or expense of upgrading hardware, manually updating drivers, etc. to get their new games working.
PC - initial outlay - $2000+, shelf life - less than a year before upgrades are needed to keep pace with the industry, continuous outlay of money.
Games console - initial outlay $500 ($800 if you buy it straight off the rack on the day of release). Shelf life - 8 years or more.