If wishes were fishes, we’d all cast nets.

And…

If wishes were fishes and cattle were kings, the world would be full of wonderful things

Meaning…

If wishes were instantly granted, we’d all swim in riches

So…

If wishes were horses then beggars would ride,

If turnips were swords I’d have one by my side.

If ‘ifs’ and ‘ands’ were pots and pans

There would be no need for tinker’s hands!

Basically the point is wishes are useless. Or more simply: “Shut up and work harder.” It’s that simple.