Don't know why he thinks MAN pax don't support the front end.
On every LH, EK, QR flight I have been on, ex MAN, Bizz class has been full or very close to it.
Virtually all Air Transat Premium seats are sold out for the entire summer.
Very often demand outstrips supply, First, when available, may be a bit thin, but there certainly is no shortage of premium pax. Northerners aren't as tight as some people make out.