After all, the advance of technology has been the advance of specialization and limitation of one's skill in other areas. John Keats, lamenting the losses from the good old days of Robin Hood, included,
And if Marian should have
Once again her forest days,
She would weep,. . .
She would weep that her wild bees
Sang not to her—strange! that honey
Can't be got without hard money!
because of course the natural thing is to be able to track down the hives and get the honey yourself.
And except for a few specialized craftsmen, you could do all your own things. You might trade because you lacked equipment, or to get better stuff, or merely because you were better at something else, but you could manage on your own.
Many fantasy wizards are able to cope with everything. That would have interesting effects on the economy if wizardry spread.