Fair sentiment but Klopp had achieved success and had a track record of building a successful team over time back in Germany before going to Liverpool. Hence, there was likely the trust by their board that he will get things right eventually when he joined them.
But with Lampard? He hasn't had the same or even similar achievement before managing us. So, we have nothing whatsoever to fall back on and have to judge him and his work based on what he's doing right now. He is still a relatively inexperienced manager and he's learning on the go. Whether it's fair or not on him, we're basically being "forced" to judge him based on his current work because he hasn't done anything of such in the past. I don't think Lampard has failed in this job but I also don't think he has fully convinced yet. Moreover, giving a manager time is one thing but we also do not want to give it for the sake of it. Otherwise, we could easily end up with a situation like Solskjaer at Man United, where he has been there for like 2 years and they are still yo-yoing between being good and bad on a regular basis.