I think it depends on that person. Although they were libero/sweeper, they played in very different tactics and under different managers/circumstances. I still think all of them would be fine in any era of football.
Franz Beckenbauer- This man can play anywhere from center-back to right-box to box midfielder in 4-3-3, he's a very versatile player and would have no problem in today game for sure. I think he could still be center-back in modern days or defensive midfielder in Guardiola's tactics( he would be an upgraded on Rodri or peak Fernandinho), a deep lying playmaker, a double pivot in 4-2-3-1( imho, he fits best in that role, if he plays as midfielder in today game) or a right box to box midfielder in 4-3-3.
Scirea- In this era, which defenders are required great passing skills( both long and short) especially from the back to operate the game. He will fit as ball-playing defender for sure. Put him with another center-back with tremendous strength and sublime in the air and he will still dominate the game like he did in his era. Another possible position for him would be dmf or deep lying playmaker.
Passarella- Probably a modern-center back in back4 like he had played under Menotti. In fact, his way of defending was almost the same as modern center-back. I see no problem with Passarella in today game, he will play superbly in today football. His heading abilities(both defending and attacking), organization, leadership and reading the game would translate well in any era. I think he will be an upgraded Sergio Ramos(in defending phase). I compare him to Ramos because both share some similar traits like great header, great leader of the game , sometimes( a lot of times) could be dirty and brutal and both have done a lot of controversial things( both on and off the pitch).
Elias Figueroa- A complete center back( similar to Van Dijk), he would be fit with anyone else in today game( from Van Dijk to another type of cb like Rudiger or De Ligt), since he could play both sweeper and stopper role. Figueroa is one of the most complete packages defenders of all time and has no weakness in his game, strong as bull, reading the game superbly and great in the air.
Sammer- Probably b2b or defensive midfielder, I don't think he will suit best at modern cb in back 4 or even central-cb in modern back3(which is very different from 3-5-2 Germany).
Koeman- He will be great ball-playing center-back in today game due to his ball-distribution( long passing) from the back and his goal scoring prowess but he needs a bit of fast-defenders to cover his weakness( pace and accleration) both in back3 and back4.
Krol (libero version)- He would be "super cheat code" in Guardiola's system, he's a perfect modern center-back in Pep's tactics( imho). Even in his playing days, he played under a revolutionary manager like Rinus Michels or a master tactician like Ernst Happlel, which was probably ahead of that time and Krol's style of playing( never afraid of challenging) was almost similar to a typical left-side center-back(not a pure libero). He has all attributes to play in modern-tactics(high line and pressing), very fast, great ball-distribution, great defensive awareness and great leadership and temperament.
Baresi- This guy would fit in any era and tactics, the greatest cb of all time.