People with 3-4k laptops. Why not desktop+laptop combo?

Hear me out here but if ur spending 3-4k for a 4090 laptop that performs like a 800 dollar rtx 4070 ti super. Why not build a 3k pc setup with like 4080 super and oled monitor. Then get a 1k snapdragon laptop that is still premium but will provide a portable solution so you can get browser based tasked done on the go???