The reason being decent processing power, nice display and well stacked keyboard. Secondly gaming laptops are notch above in build quality than regular laptops and OP wants to use it for 4-5y. If OP would go with pro laptops then price range would also go higher. I just provided few options as...
3D printed 3.5 to 2.5 caddy - 700
Toolless design, Can accommodate two 2.5" SSD or HDD. Fit in standard 3.5" Drive bay.
It has two HDD Slide trays. One tab of a slide tray has broken(circled in pic) but has no effect on functionality. I'm using it with no issues. Other one is completely fine...