Glenn, you're making two different claims and neither one proves what you think it proves.
First, "Reformed Egyptian" doesn't have to be a standalone language recognized by modern scholars. The Book of Mormon itself says it was a modified writing system used by a small group of people:
"And if our plates had been sufficiently large we should have written in Hebrew; but the Hebrew hath been altered by us also... we have written this record according to our knowledge, in the characters which are called among us the reformed Egyptian." (Mormon 9:33-34)
Notice it doesn't say "the Egyptians called it Reformed Egyptian." It says "called among us." In other words, it was their term for an adapted script.
Second, the argument "we haven't found an example of it, therefore it didn't exist" is an argument from silence. We have thousands of ancient languages, dialects, and local writing systems known from only a handful of inscriptions, and many that disappeared entirely. The absence of surviving examples is not evidence of impossibility.
Third, the irony is that critics often demand archaeological evidence for every detail in the Book of Mormon while accepting countless ancient texts whose originals no longer exist. By that standard, much of ancient history would have to be discarded.
Finally, you're still appealing to authority rather than addressing the actual evidence and arguments. Latter-day Saint scholars aren't saying, "Believe Joseph because Joseph said so." They're pointing to things like ancient Near Eastern patterns, Semitic wordplays, Book of Abraham parallels, Hebraisms, chiasmus, and other features Joseph Smith was highly unlikely to have invented in frontier America.
You can disagree with those arguments, but simply saying "Egyptologists disagree" isn't evidence. It's just another appeal to authority.
The real question isn't whether a majority of scholars accept Joseph Smith. The real question is whether the evidence is best explained by fraud, coincidence, or revelation. That's the debate.