Religious revivals do happen, y'know - often in response to major natural disasters, so the current pandemic could spark one.
But you were the one who said that once people reach adulthood they very rarely change their religion - and you are correct.
And on major natural disasters etc - can you give me an example of one that has produced a revival in the religious attendance in the UK in my lifetime (I'm 53). I agree that sometimes a major incident results in churches being used as places to mark the event in the days and weeks afterwards and often many people attend, who might not have been in a church for years. But that isn't a revival as those people will go straight back to non-attendance. I suspect (and I'll look up the research on this) that major events produce a very short term uptick in religiosity-linked behaviour, but increase the decline in the longer term as people's faith is shaken further on the basis of 'how could god allow this to happen'.
On this particular one I imagine it will be detrimental to church attendance in the long run. Firstly, and most obviously, the increased death rate which is particularly associated with the oldest (and therefore most religious) age group. Secondly regular church goers will not have attended for weeks, if not months, once we are fully out of lockdown (I can't imagine religious gatherings will be top priority for the government to allow in the first stage of relaxation). Plenty of those people will head straight back to the old attendance pattern, but there will be some who, having got out of the habit of attending, just wont go back to it. Frankly I'm struggling to see why a non-religious, non-church attending person (the vast majority of the population), would suddenly think, post-lock-down, hey do you know what I going to go to church.