> Early attempts at decipherment were also confounded by numerical errors and the sloppy writing of the original tablets
As you would expect. Imagine writing receipt slips by hand.
> Jacob Dahl believes that some of the signs are being used to indicate syllables, making these the first texts in the world to use a syllabary.
Well "some" here means "not many". Probably names.
The reason that decipherment of Proto-Elamite stalled is not for lack of material. It's because accounting is boring. That's not to say I wouldn't want to participate :-)