  (Abridged) Typically large telescope construction and operation costs scale
up faster than their collecting area. This slows scientific progress, making it
expensive and complicated to increase telescope size. A metric that represents
the capability of an imaging survey telescopes, and that captures a wide range
of science objectives, is the telescope grasp -- the amount of volume of space
in which a standard candle is detectable per unit time. We provide an analytic
expression for the grasp, and also show that in the background-dominated noise
limit, the optimal exposure time is three times the dead time. We introduce a
related metric we call the information-content grasp, which summarizes the
variance of all sources observed by the telescope per unit time. For
seeing-dominated sky surveys, in terms of grasp, etendue, or collecting-area
optimization, recent technological advancements make it more cost effective to
construct multiple small telescopes rather than a single large telescope with a
similar grasp or etendue. Among these key advancements are the availability of
large-format back-side illuminated CMOS detectors with <4 micron pixels, well
suited to sample standard seeing conditions given typical focal lengths of
small fast telescopes. We also discuss the possible use of multiple small
telescopes for spectroscopy. We argue that if all the obstacles to implementing
cost-effective wide-field imaging and multi-object spectrographs using multiple
small telescopes are removed, then the motivation to build new single
large-aperture (>1m) visible-light telescopes which are seeing-dominated, will
be weakened. These ideas have led to the concept of the, currently under
construction, Large-Array Survey Telescope (LAST).
