There may be an error in my math.
For one thing, quality comments take time and effort to write. Suppose a comment takes 5 minutes per to write per karma point earned. Then 32553783 karma points are worth 32553783*5/60/24/30 ≈ 3767.8 man-months or approximately 314 man-years not spent doing something else.
This isn't to say that HN comments just lose the authors (or their employers) money due to opportunity cost. I would not be surprised if for a number of HN users their commenting led to new clients and business partners, not to mention exposure for their open source projects or simply memorable discussions the impact of which is harder to estimate in monetary terms. (For example, the recurrent discussions about Stoicism have made converts.)
Then some comments may not make the author money -- at least not as directly as getting a new client -- but may be worth a lot in terms of the money they make others; patio11's long comment history comes to mind.
Since the usernames are not queryable via an integer (e.g. user?id=1235654321) it's not exactly the most trivial of things. You'd have to go through an endless amount of posts, get every possible username from the comments, go through all stories submitted, grab their usernames, and then loop through the HN API and grab karma info.
select sum(karma) from user_data;