Basketball was promoted as mano a mano,star vs star. So if the other star was scoring you need to match his scoring output and win the game. Its different in today's league with multiple stars on the team often times.
Tbh, the whole "guarding your matchup" more or less stopped being a thing once LeBron, Harden, Luka etc pioneered/popularized heliocentric offenses... aka excessive mismatch hunting thru the PnR. Obviously guys like Steve Nash been manipulating the PnR forever and occassionally taking advantage of a bad switch, but the aforementioned guys took it to another level.
i.e. Iguodala may start off on a Lebron or Harden... Kawhi may start off on a Luka.... but it's fleeting because they're going to force the switch to find Curry or Lou Will or whoever the weakest link/most flat-footed big is on the court.
Some would call it cowardly, others would say strategic/econcomical. Depends on our perspective.