Makes sense, that the manufacturer would set the bevel with the razor raised off the stone, that can explain why there is very little visible hone wear.

As far as customs, there are still several makers who use tape when honing a new razor before sale.

I have also seen vintage razors that have clearly been honed and have reduced in width but have no spine wear.

Wedge razors also seem to be majoritarily honed raised off the stone.

So is it possible that the frequent instruction of wearing the spine when honing simply the result of what was easiest for the consumer to follow and thus it became the "Tradition" ?