The dilemma for such impresarios is the same as it is for all sellers of nonessential, disposable goods: how to convince a mass audience to continue buying what they don't really need.
The private lives of such impresarios as Boris Thomashefsky (grandfather of the conductor Michael Tilson Thomas, David Kessler and Jacob Adlerr were turned into material for the stage, and their weddings, funerals and family disputes were enacted before packed houses that wanted to be part of their heroes' lives.
There were many such local impresarios of bloc voting: the uncle of one politician I spoke to defeated Khan in his very first election in 1997; he had now brought, he claimed, a 25-kilometer-long convoy of supporters from his tribe to the rally.
From his headquarters in Thailand, which seems a suitable location for such a zany impresario to turn out his memoirs, Simon Napier-Bell keeps up to date with a pop world that has changed beyond recognition since he rose through the ranks but is in many ways exactly the same.
Impresarios such as Gerard Mortier and Roland Geyer have also declared the system unsustainable.
The differences between then – when impresarios such as Bernard Delfont and Lew and Leslie Grade dominated – and now, when "somebody who sings one song is a star overnight and gets millions of pounds", are not lost on him.
Morley was introduced to theatre photography at the Royal Court by Lindsay Anderson who commissioned him to photograph Serjeant Musgrave's Dance in 1959, the first of more than 100 stage plays he photographed for impresarios such as Oscar Lewenstein and Michael Codron.
Sweet-voiced and agile, Studholme was still singing Despina in 1974 – "evergreen … deliciously knowing … the voice as trim as ever, the gait as youthful," said Stanley Sadie; and her appearances singing Strauss, Lehar and at various "Viennese Nights" staged by impresarios such as Victor Hochhauser and Raymond Gubbay continued until at least 1978.
Catch up on the comedy that never went out of style with some classic Laurel and Hardy shorts, René Clair's brilliant 1928 screwball comedy The Italian Straw Hat, and documentaries on bygone impresarios such as Fred Karno, Will Hay and even Kenny Everett, usually with live musical accompaniment.
It featured the instrumental wonders of jazz impresarios such as Duke Ellington, Count Basie and Jerry Roll Morton.
