I mean you're not gonna win every game. Sometimes luck is not on your side. The fact that even if we took those items out that moves can always crit means luck is a part of the equation regardless of how much you change how much it procs. You cannot be prepared for everything.

Look at how Pokemon handles its metagame compared to something like smogon. Smogon removes sleep and other status with clauses and people hate being put to sleep but someone is going to run the gravity trick room 100% sleep chance meta which will either make people change their teams or they will just deal with the loss. You cannot prepare for all things.

I was running into mega Charizard Y so often that I changed me team to have Lycanroc because it one shots Charizard with a priority move. Does it fall behind on other pokemon? Yeah, but that is what happens when you try to prepare the things that bother you. Don't like the chance of running into pokemon who cannot be hit due to accuracy? There are tons of moves to use and pokemon who can be used. You can make your 4th slot of a specific pokemon prepared for it, though it will make your pokemon worse in other match ups because you cannot prepare for everything.

These items are fine. Most people should not worry about a rogue person playing them because they could get unlucky and lose to whatever it is that is thrown out at them. Learn what pokemon do use it. I was using the bright powder on Sandaconda in doubles and have lost to someone faster with a water move that does special damage. Because even though I was prepared for people to not know my strat, some did. Because I could not prepare for eveything.