For a certain type of person, sales is much easier - if not completely natural. For others, the same could be said about technical pursuits.

I don't think it's possible to make general statements that one is harder than the other, because it depends very heavily on the person involved.

I disagree. Sales is fuzzier than engineering and requires a different set of skills and methods to resolve problems.

They're both hard.

Rockstar salespeople are just as impressive in action as rockstar developers.

The skillset is fuzzier, but the results are not fuzzier, as reflected by common practices of sales compensation across the industry.

I'm sure selling mediocre, repackaged, off the shelf tech is harder than engineering it. Standing on the shoulders of giants gets us a long way quickly (and easily). IMHO engineering is more valuable; I define value as the expansion of possibilities & opportunities (to sell).