Wirebonding a massive footprint is less yielding. Also the large packages take up more room on JEDEC processing trays in semiconductor manufacturing and leads to higher costs due to low chip/tray throughput. Furthermore, warpage of large packages is of concern and so is inability to ship in Tape & Reel.

All serious stuff in IOT is WLCSP which has an insanely small footprint __and__ z-height.