How are PCIe Expansion cards not way more popular

NVMe SSD PCI-e Expansion Card m2 expansion slot PCIe slots on your motherboard are used to connect a host of different things — namely graphics cards and expansion cards of all kinds (sound, Ethernet, Wi-Fi, m2 pcie 40 in 30 slot M2 expansion slot, the native BIOS support NVMe, adding another M2 slot through the adapter should not raise compatibility issues; variants

m2 slot types My ten year old PC uses DDR3 memory and PCIe expansion slots, the x16 slot is occupied by the graphics card, no slot on the motherboard