I specified the Ultimate & Blade frames with rear wheel cut-out, no other frame in the current market offer the same feature on ti frames, due to the difficulty, tooling & man-hour required to fabricate such seat tube.

Carbon fiber frame may be easier to fabricate, but they certainly do not last a life time as ti.

Steel frame rust, they need paint to protect the frame & they do not cost a lot less, do not last a lifetime for most people living with rainy weather.

My Lynskey disc frame was purchased brand new under $500 from eBay back in 2018, posted many pages back in this thread, likely last longer than I can pedal.