First 50 clears of savage has 65% SMN vs 20% BLM vs 15% RDM, ranged were 88%DNC vs 11%BRD (that was pre-mch-buff). Current TOP clears are 836 SMN vs 144 RDM vs 180 BLM; phys ranged see 550 MCH vs 509 DNC vs 97 BRD. High-end prog strongly biases AGAINST RDM and BRD despite the "utility".

I can speak to RDM a lot more. The class just does not bring enough damage for player effort compared to SMN, both in terms of max and average. In the expansion update there were also design oversights. The mana costs were universally nearly halved, but enchanted reprisal costs the same as it did while doing less damage (2.2s gcd extended to 2.5s). Combo finishers generate the same mana as it did which make them critical for your mana generation, while you still lose everything when dying - this is problematic in prog. (remember SMN keeps its legos).

I can't speak for high-end BRD, but it is proc hell, and DNC is just much easier to play while still having the potential for more rDPS than other non-BLM ranged. The fact that songs need a target to cast is also absurd since that requires a target dummy fight to use BRD's max potential synchronizing song cycle with 120s feels just off.

"Providing support" - a 120s 10% magic only mit is not THAT good. The 5% healing up is very overrated and is basically ignored. The devs just don't play these class, at least not in high-end play-tests it seems.

Why can't BLM be just buffed? Because RDM being bad and SMN being braindead is dragging the role. Buffing BLM without fixing RDM will just make high-end mages a complete mess.