One person isn't a clan dude .
Sasuke could have done this himself or just revive them with rinnegan hell even edo tensei.
The statement you gave is exactly why your wrong.
Sasuke is one person and i am nowhere near being the best mathematician in the world but i most certainly counted more than one shin.
Which brings me to another point.
All the clans with kekegenkai kept it in the blood.
The uchiha bloodline can't live on through sasuke alone indefinitely and will dilute eventually.
Shins offspring can eventually breed with each other as there will be a higher percentage of half blooded uchiha through the shins at one given time with each offspring potentially making the blood more pure down the line.