Before anyone asks, it was cell phones going stratospheric in popularity, with T-flash (sdcard) storage that won the flash format war (excusing USB obviously). Everything else was left to rot.
SmartMedia was a pain in the ass because the 5v and 3.3v cards weren't immediately obvious. You could spend a lot of money on a card only to have it physically fit but not work in a device or reader.
With CompactFlash and MMC (and SD) if they physically fit they generally worked.
CompactFlash is still used in professional equipment last I've checked