The most serious difficulty with alien contact is time. The potential
for scattering across time by different rates of development would
make it highly unlikely for simultaneous co-existence to occur within
any useful radiius. Even assuming teeming intelligent life in the
universe a century either way in development and would make radio
contact with others extremely unlikely. A century is a nanosecond in
terms of the useful age of the universe. The problem is not one of if,
but when.

Based on our own example the likelihood is for a slow cyclic existence
between technological development and population crashes. Perhaps
pandemics or glabal wars are a vital factor in the survival of all
dominant species with our very slow rate of psychological and
organisational development? A far smaller population learning from
what went before makes quite good sense as a longer term survival
pattern. One can but hope for something more benign to pull us up from
our present nosedive into total systems overload.

The next problem becomes the time it would take to develop global
radio systems and light travel from a much smaller population base and
its inevitably more limited funding. Particularly if there is no
pressure towards such developments. A quiet pastoral existence might
seem infinitely preferable to the survivors of repeated global plagues
or wars. Technology might even be seen as threatening and supressed
over many millenia. An anti-technology superstition might easily arise
in the guise of religion from a single charismatic figure. Our
universe might be full to the brim with happy, post-technological
peasants. None of whom gives a jot about saving us from
ourselves.