I like the way it was explained to me. Think of diving like martial arts with various degrees of belts. A new recreational diver is like a white belt and who then moves through the various colors as they gain experience and more training (AOW, Rescue, Specialty courses, diving experience). A technical diver is a diver who has progressed in their skill level through training and experience to be black belts.
Now regarding equipment, the technical diver typically has different equipment and ALOT MORE OF IT! They will almost universally use BP/Ws instead of standard jacket BCs, they will use double tanks with isolation manifolds, usually multiple sets. They will use various size stage/deco bottles slung off to one or both sides for their very compless gas needs. They will often use very expensive lighting systems (it's dark down at 200'). They almost universally use expensive drysuits. They use complex gas mixtures involving oxygen and helium. Nowadays they will sometimes use rebreathers and even scooters. After doing some number crunching, if you assume you've progressed to the point of having very solid basic skills (buoyancy, trim, situational awareness), the cost of moving to entry level tech can easily be in the $5,000-$7,000 range. Moving up in technical diving becomes VERY expensive due to the cost of training, equipment, equipment maintenance and diving (charters). The cost of preparing to do a dive on a deep wreck (200') when you include training, equipment and experience can easily top $15,000.
