What league are you watching that you would think that a combo guard who is at best a below average starting option would be in high demand?
The league is so stock full of productive scoring-focused lead guards that Deangelo Russell just had a season where he averaged 21 points and 7 assist on 51% EFG and yet he's closer to the middle of the point guard pack than the top of it.
D'Lo also has the benefit of actually possessing court vision, a useful trait in a point guard that Terry Rozier does not possess.
Even in his much lauded playoff run, Terry only put up approx. 16 pts 5 ast 5 reb 1 stl on 40/35/80 shooting with just a handful of free throw attempts.
For his career, Terry has a TS% below 50%.
If you want to just look at Terry as a starter, for his career he averages basically 14 pts 5 ast 6 reb on 40% shooting from the field. That's mediocre.
Terry Rozier is mediocre by any measure, including projecting his 2018 playoff performance to a full time starting gig, which is a dubious proposition at best.
If you're a team without a good starting point guard and you don't have a player at some other position who can perform lead-playmaker / shot-creator duties, you can just be bad for a year and select a guy in the draft.
Seems like in almost every draft there's at least one guard, if not several, with the skillset to average 15-20 points on solid efficiency as a primary pick and roll ball-handler.
If you don't want to draft, just wait around for some team to draft a Monte Morris or a Fred VanVleet and then try to snag that guy in free agency.
Only a foolish or desperate team would pay good money for the right to have Terry Rozier as their starting point guard.