I remember a few posts on MT about ransomware that bypassed the protection of Kaspersky. Some time ago, I posted an example of ransomware that bypassed Kaspersky, Microsoft Defender, and most tested AVs. No AV can block/detect all possible malware (including ransomware) in all scenarios. This is especially true for simulations with custom-made samples. Furthermore, the AV vendors do not use all possible methods of fighting ransomware even if they know how to do it (other security layers, false positives, complexity, etc.).
I think that the problem with such videos is the expectations of watchers. If the video creator does not clearly say that the video is only an example of something that is already confirmed by reliable research, professional reports, tests, etc., people will understand that the video is going to prove something. To be honest, the author did not say anywhere in this video that AVs that blocked/detected the ransomware simulation were generally better than others. But if we look at the comments, most people take this video very seriously as proof that some AVs are winners and the rest are losers, which is untrue. This video only shows that AVs can use different methods to fight ransomware.
Generally, Kaspersky indeed has one of the best anti-ransomware protection. But, this cannot follow in any way from the video with one sample.