Yes, this is one of the papers I have been citing, but mostly this-

"The disease was correctly diagnosed within 2 years of the onset in 80% of cases".

which means that 20% of the patients, having a potentially treatable disease, that should be treated as early as possible, are not diagnosed even after 2 years!

"The more severe the disease at the first observation and at the maximal worsening of symptoms, the lower was the proportion of remissions."

I would think (as the authors of a review citing this paper did) that some of those patients, had they been diagnosed earlier (and not after more then a year), would have a better chance of remission.

"even with treatment the proportion of remissions was lower in patients with more severe disease at the first observation. the authors interpreted this as suggesting that early diagnosis and intervention may improve prognosis. only 58% were correctly diagnosed as MG during the first year of their illness, and 80% within 2 years. (M&N, april 2004, p. 484)".

Also, take into account that patients like Chloe Atkins that never fulfill the diagnostic criteria for myasthenia are not included in those statistics!
And I do not think any one knows (or cares to know) how many patients like her there really are, that do not have the emotional strength required to fight this, and just succumb to their illness and live (or die) with the diagnosis of "functional/coversion disorder".

If you take into account that about 50% of patients with a neurological illness (eg-those that are referred for evaluation in a neurology clinic, by other physicians) are diagnosed as conversion/functional disorder, because like Chloe Atkins they do not have "objective" evidence for their illness, you may have some possible idea of the extent of this problem.