rdm masts use thicker walls. To achieve similar you up the diameter, this can be seen at rear of north, mauisails & prolimit carbon booms.

Carbon will outlast flex cycles of alloy by a considerable amount, fibrespar? tested this years ago & it was something like 4000 cycles for alu & 20000 for carbon. However carbon is less impact friendly, it shatters under point load rather than bends. Everytime bar 1ce ive been able to jury rig a broken alloy boom & sailed in. Every carbon boom resulted in a swim because the tail was destroyed.

Over 220cm definitely go for carbon imo, carbon gives better performance for big guys- boom flexes effectively shortening, sail draft increases & moves around with gusts/chop.

If a product is marketed for someone of a particular size then fine- rdm booms always been that way. But a product that is marketed for the general sailor shouldnt have you're too heavy as defence for the product breaking (within reason).

You should rarely have to swim in if you break a boom- only if clamp or tail breaks in direct centre & you loose all pulleys/cleats. Just swap the existing arm to opposite side & use extension with cleats still attached. If it snaps mid arm & you bail before backend breaks then use harness line to keep both halves together. Both are a soggy tiring sail home but it beats swimming.

been sailing since 1991, around twice per week.
had 2 years off, so thats 16 years sailing and can only remember breaking one boom arm.
mostly use 5.0m which may explain alot.
having been using north carbon boom for last 6/7 years. still feels as stiff as when bought 2nd hand.
i bought chinook carbon to fit my rdm mast and feels great.
forgot my boom once and borrowed a ali boom with plastic front end, it took me half an hour to figure out why i had lost 2/3 knots of speed.
the more extension you use the boom loses heaps of stiffness.