Misquoted and misleading. The link actually says 40% are employed in service jobs that are "often" low-wage. Many service jobs pay very well indeed.
Physicians and attorneys are service jobs. Consultants often earn well. Most government workers are in "service jobs." As we have seen recently, many of them earn upwards of $100k.
I think you misconstrued the sense.
It would have read better as “low-wage, service employees” being that as a division of the category “service Employees” there is a sub-category called “low-wage service employees”, which would exclude your “high-wage service employees”.
Lurking’