In academic circles, over the years, considerable intellectual endeavour had gone into showing that markets are efficient – whatever the convoluted and volatile path of financial prices over time, this is not only rational but indeed optimal (see, for example, Garber (1990)).
The rationale for any one participant in pushing the price further away from its fundamental equilibrium was often along the lines of the “greater fool” presumption – however artificially high the price, someone would pay more for it later.