Weird example. When would you need to sightread a piece like that? Also, it's not that hard if you take the printed tempo or a little under that. Lots of ink on the page doesn't necessarily mean it's fast and difficult. Although the rhythmic errors (added or missing beats and bad notation) in bars 6, 22, 24, and 30 would be pretty confusing.
I was once asked by Pierre Boulez to sight read Elliot Carter at a live audition. In that case, I was in over my head. There are probably people out there who would have dominated that reading, but I'm not one of them. Yet.
It is weird. I don't know when anyone would be called to read it. But it does fit in the category of "any" piece of music, which it is. I also am willing to bet that if I put it in front of Lee Rocker he would not be able to play it correctly, despite him being a professional for many years.
Therefore the answer is: No, it is not realistic to put any piece of music in front of a professional double bassist and expect them to read it.
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