As many have said previously, many tech divers have no additional weight. Particularly if they have a stainless backplate, steel twin cylinders and steel sling tanks, all very weighty and stay heavy even with little air in them. Add to this one can have a twin bladder in the wing for backup, SMB and lift bag and dry suit for lift, redundant air supplies, backup mask, 2-3 torches etc etc. You soon see that tech diving is all about managing risk with backups and plans.
Recreational diving is simplistic diving, one mask, one lift system, one air supply (floaty aluminium cylinder when near empty) and a buddy, weights to keep you down because buoyancy is crap to start with. Slowly over time you add to that with gear and experience, weights come off. Then you decide you enjoy diving a lot and become rebranded, throw away the weights and take on a pack full of experience, knowledge, gear and planning.