The lure of money, where the risk of direct detection remains minimal makes cheating inevitable. Incentives are strongest with chess content creators, such as Hikaru.
Securing direct evidence is a near-impossible task. Direct evidence means, tracing through game statistics and behavioral cues. The evidence should be rock solid before starting to accuse any individual.
This is a systemic problem. While Kramnik and Carlsen might be right, their approach poisons the game deeper.
Perhaps a better tactic would be to abstain from naming culprits. Instead, they could have provided anonymized statistical evidence and explained their methodologies. Public consensus before naming the names could have been a plausible.
Systemic problem requires systemic solutions. Top players might have to play significant amount of their games in secure "SCIF" under observation, or something, to keep playing.