1TB NVME SSDs are cheaper:

https://www.amazon.com/Samsung-Inch-Internal-MZ-76Q1T0B-AM/dp/B07L3D19MY/ref=sr_1_4?keywords=1tb+ssd&qid=1562986938&s=gateway&sr=8-4

https://www.amazon.com/Crucial-1TB-NAND-NVMe-PCIe/dp/B07J2Q4SWZ/ref=sxin_4_ac_d_pm?keywords=1tb+nvme&pd_rd_i=B07J2Q4SWZ&pd_rd_r=0a1b277a-c579-4952-bdd8-b39376f63fc9&pd_rd_w=7HMWs&pd_rd_wg=bhjFG&pf_rd_p=64aaff2e-3b89-4fee-a107-2469ecbc5733&pf_rd_r=5YW8TQN6YF9J81YAQQRR&qid=1562986956&s=gateway

OP is right, 2.5" AHCI is dead. Next-gen consoles will have PCI 4.0 NVME drives in them, so games will be designed with NVME SSDs as a baseline requirement.