Probably the most overrated tenet in football you're parroting here & its not nearly as important as fans and some old-fashioned coaches think it is. You don't necessarily need a bondafide #1 or this or that type of cb & What's always been underplayed is chemistry, experience & scheme fit. Im saying what i'm saying about the Texans b/c they have all of the above in droves...….imo of course. Most of the Texans' secondary & defense as a whole have been in this system for years & We've seen how good they could be defensively when healthy & with great playcalling. & that was without Watt & without talents like Mathieu at safety & Colvin.
Tampa 2 Bucs secondary wasn't locking anyone down specifically, they depended on prime Sapp, Rice and Brooks to wreak havoc so that there zone coverage didn't break down.
2013-2016 Legion of Boom got all the headlines...…but Sherman primarily stayed on1 side of the field & Avril, Wagner & Bennett all made life hell for qbs.
We all saw how Von Miller damn near singlehandedly took over in the playoffs in 2015...Think Harris and Talib were complaining?
Hell the eagles last year didn't have anything special at CB last year...damn good secondary and defense though.
So I don't see anything wrong with playing zone & letting the front 7 do what it does. Most of these supposedly good secondaries above you're probably thinking the Texans are far inferior to all had bad ass front 7's that took them from being pretty good to downright smothering & playmaking.