  We propose a simple theory for the dynamics of model glass-forming fluids,
which should be solvable using a mean-field-like approach. The theory is based
on transparent physical assumptions, which can be tested in computer
simulations. The theory predicts an ergodicity-breaking transition that is
identical to the so-called dynamic transition predicted within the replica
approach. Thus, it can provide the missing dynamic component of the random
first order transition framework. In the large-dimensional limit the theory
reproduces the result of a recent exact calculation of Maimbourg et al. [PRL
116, 015902 (2016)]. Our approach provides an alternative, physically motivated
derivation of this result.
