I think that the reason for the shift towards light to mid weight bats that pick-up well is actually fairly simple: economics
I used to work in the cricket equipment/retail industry (I won’t say where). And in my experience bats that were 2.8 to 2.9 were by far and away the most popular for the vast majority of people, with some preferring a slightly lighter bat, and the proportion of those who wanted a bat over 2.10 being fairly low. It seems to me to be basic good economic/business sense to produce more bats that most people like, especially in tough times such as these.
I think the number of people who think they need a very low sweetspot on their bat ( meaning it probably will pick up like a railway sleeper more times than not) is dwindling. I think the logic behind that was always flawed (unless you’re overseas on subcontinent style pitches). Have a look at your bat… I have very rarely seen someone’s bat that was covered in lots of marks toward the bottom end of the blade. In my experience most amateur cricketers use most of the face and the better players hit more balls somewhat centrally and around where a mid blade sweetspot is usually positioned. As such, with modern dried out willow, a mid blade sweetspot, not too much wood in the toe and an overall weight of about 2lb 8oz, the bat is going to pick up very nice and light. I think the market for funky profiles or big heavy bats is limited. There is a good reason that most pros use fairly similar profiles (there are often slight differences of course but they are generally not a huge range of profile shapes that I can see when I watch). I also think with how good bats are these days, you don’t really need a massive bat, if you play a half decent shot and have a nice bit of wood, chances are it’s going a good distance!
I saw a comment making fun of people who ask for exactly 2.8 and add a grip making it heavier, I feel this was unfair and I will explain why… Personally I don’t use two grips, I like a fairly thin handle, and I prefer the feeling one one grip as I feel the sponginess of two grips gives me less feel for how the bat is responding and slightly less control of the bat face. I prefer to carefully apply some zinc oxide tape around parts of the handle I’d like to thicken ever so slightly to get it to where I feel comfortable. I also apply small pieces of older grips around the top of the handle (where the pommel would be if it were a sword) to get the bat to pick up to my liking. However, for consistency, I like to weigh my bats with a face and with just one grip on them, no counter balancing grips. Customers like those mentioned above may well know that they like a 2.8 bat with a second grip on top of that, and that’s fine. In the same way I know I like a bat that’s 2.7-2.85 with some tape and some counterbalancing until it feels right. For me, the mistake is to not take into account the weight of a face, especially if you are using a good quality clear antiscuff that can add weight in a way that makes it feel heavier.