It's the exception now. It wasn't always. Picking specialist catchers was usually a reactive measure after missed chances affected results.
Either side of the First World War the issue was mobility in the outfield and ability to throw in from the boundary. Poor fielding was highlighted in the press. Digby Jephson wrote in 1901:
To write well of the fielding in 1900 is but to forge a romance that exists nowhere, save in the writer's brain. Taken as a whole the fielding has been bad, thoroughly bad. The energy, the life, the ever-watchfulness of ten years ago is gone, and in their place are lethargy, laziness and a wonderful yearning for rest.
A great batsman having produced a colossal score seems content with his performance. He loafs in the field. It would be a good thing for cricket if many a great batsman could be confined to the slips, for there there is always the chance of a sudden shock, a sudden realisation that he is in the field to do some work.
Many cricketers returned from the war with wounds and disabilities that affected their mobility and throw. It was sometimes claimed that Middlesex men Hendren and Robins partly owed their England careers to being based at Lord's. It was equally true that they were far more athletic than their rivals in the field.
So I want to make two points and then wrap up this conversation.
So we have two scenarios and what would be reasonable reactions to solve them.
Your batting is collapsing and you're not scoring enough runs, you feel like your scores are constantly below par. How does one fix that?
Second scenario, your fast bowlers are producing edges, but they're being put down and you're missing out on crucial opportunities. How is that fixable.
I imagine the best solution to the first would be to strengthen the top and middle order. However, somehow the notion arouse, specially in the SC apparently, that the best way to do that would be to bolster the lower order, often weakening the bowling in the process, still making it harder to actually win.
Now which of those two solutions seem more viable or even sound?
For the second scenario, it's straight forward. You strengthen the cordon. Now how, you ask? There's probably been less than a handful of teams in history that had a quality lineup 1 to 6, with at least a couple below test standard batters hanging on through the supplementary skills of bowling and or catching.
Now to the second point.
Apparently where one was indoctrinated into the sport seems to have an impact on ones perspective. Based on conditions and experiences.
The subcontinent has been traditionally slow and low, the bastion of spinners and often not the most skilled ones with the bat. Slips would not have been much of a priority and especially not at home, and as it's been primarily to the spinners, you could get away with just one good one.
I grew up during the dynastic years of the WI, and it was aggressive batsmen, fast bowlers and the best cordons imaginable. It was same for the Aussie team there after and the SA team after that as well.
You can't win in the traditionally WI, Aus, Eng or SA without being able to catch in the cordon. That's where the dismissals happen, it was a hyper focus, a priority.
Today with more limited over matches than domestic first class ones, it's lost its pride of place and the quality has plummeted.