I wouldn't say they were chumps or were hustled... but clearly circumstances do change.
Someone argued earlier that institutions like AIG either did poor DD prior to buying or did poor DD after selling... but I don't think that's a fair assessment. The risk-return perspective of any investor - retail or institutional - changes with each new piece of information. This was supposed to be a rocket docket, but things have taken longer than expected. Willful infringement was expected, but the prayer never came, and then in the end it's potentially back on the table. Royalties were being calculated 6 years from the date of filing, then the laches ruling was handed down. The jury came back with a positive verdict, but the math was confusing to many and expectations were re-adjusted once again. In the end, most are still here waiting for the final rulings and uncertainty still persists.
I don't think anyone can be wrong for choosing or not choosing to invest in a speculative story that has yet to play out.