They did so it's not an accurate comparison with modern day cricketers. But, even so, averages in the teens and low-twenties were not great for specialised batsmen. I just a had a quick look at the averages for a few batsmen of that era and found that all of them (none of them were test players) had averages in the low 30s.
Let's take a look at neighbouring county Hampshire. Besides Greenidge and Richards (surely two of the best overseas players ever), they had Turner (av 31), Jesty (av 32) and Gilliat (av 29). They also had two very handy all-rounders in Peter Sainsbury and John Rice. That's just one county: there'd be a similar story at Middlesex, Surrey, Kent etc (and we won't even talk about Yorkshire).
