I don't entirely agree with the notion that the Proscription of 1746 wiped out kilt-wearing in the highlands as an everyday, common practice that reemerged via Walter Scott as a strictly formal/ceremonial habit.
The Proscription was not universally enforced, especially in remote highland and non-Jacobite clan regions. Period paintings from the Proscription period show instances of everyday kilt-wearing still going on in non-formal contexts: hunting, cattle droving, sheep herding, etc.
The Clearances probably dealt a worse blow to common highland dress that the Proscription, but everyday, non-formal use of the kilt apparently maintained a precarious existence in the highlands through the 19th and into the early 20th centuries, again if paintings and photographs are accepted as evidence.
The photo of the boy with the trout is ca. 1910. Here's another from the same period:



At leat three of the young fellows are kilted, in hardly a formal or ceremonial manner...!