why? I mean, I get why you could think it isn't necessary, but not how you can think it's bad. Why do you think it's bad?
It would make Alchemist an autobuy almost all the time and Familiar almost all the time. They are already good enough. I think the possibility of not getting $3P on each shuffle is part of the risk assessment you need to make. Sea Hag, Ambassador and Swindler's swingyness is comparable, and I don't mind them either.
And it is completely false that you lose the game immediately if you fail to get $3P on the first shuffle, because Familiars tend to miss shuffles and luck may even out, and Alchemists may always find a Potion to be topdecked, or never, so you can also have a swing of luck. Minimizing luck is good when you can do it without altering other variables. Making Familiar super-powerful because you can buy it everytime the Potion comes up would reduce the variety of the game, and consequently, the fun.
Can me selfish
I don't think I want to call you selfish, though I don't mind if that's what you really want, but I sure won't be canning you no shellfish. Go to the supermarket if you want some.