Because you're missing my point. Why didn't they ever improve it over almost 20 years .
And again I say, Ambrose had some of the absolute worst wicket keepers in history, so do we adjust for the time he had Murray and Browne?
The west indies, Australia etc didn't have good cordons and fielding support by accident. It takes leadership, skill and practice, Smali said it wasn't that big a factor when Imran was around because it wasn't tolerated. How can you justify having horrible support, and doing nothing about it for a decade. Sacrifice a few runs and get a specialist in at 2nd and shuffle around him, have more catching drills.
There's an anecdote about a fielder dropping a catch while Viv was captain, and it goes that he was banished to the boundary, and even when he reached there Viv kept motioning for him to go back further.
And again, every bowler and batsman had challenges. Do we go back and adjust for them as well? This argument to justify Wasim as being the best because.... Is just ridiculous.
And yes, catching is extremely important, it played significant roles in all of the great teams in the past and contributed to the successes of McGrath, Marshall, Hadlee, Ambrose, Steyn etc..but two points, how do you quantify how much his numbers would have improved, and why would we. Why didn't Pakistan do more to provide that support and why should we single him out to adjust figures when it can be said that most players faced challenges. That's my point.