I think most people buying a $2000+ laptop keep it for more than 18 months. I know I would.
This is about a 3 year upgrade cycle. Since 2010, it seems to have accelerated, but mainly due to work (I've bought only one MacBook for personal use since 2010 - all others were company computers).
It's strange that not just games, but even software requirements are indirectly influenced by consoles.