We're heavily influenced by our human perspectives. Alien life could have just figured out a way to not spread uncontrollably like a virus through the universe, burning resources and constantly destroying things then moving on. Coming from our human perspectives, this type of mindset is very difficult to imagine.
This again runs into the problem of
all aliens choosing to do exactly this with no exceptions within the visible universe.
Secondly, the spread of life is a more general phenomenon than the particular variety associated with humans. Imagine the absurdity of discovering a counterfactual Australia with no life on it--would a good explanation take the form:
natural selection just decided against it? We are talking about growth rates that are balanced right at 0% for cosmologically significant periods of time to prevent either ubiquity or extinction. Global annual energy consumption is currently at ~10^21 joules. If that grows by 1%/year, the entire power output of the sun will be used in 3000 years and the entire output of the galaxy in another 3000 years (so clearly the speed of light would be the limiting factor in the latter case). Similarly, a growth factor less than 0% would result in extinction in a relatively short period of time. There would have to be an incredible amount of homeostatic control to prevent either scenario over cosmological timescales, which requires a very exacting explanation. Such a finely balanced state of affairs would be subject to failure due to value-drift or defectors over cosmological timescales.
Thirdly, "burning resources" is something the universe does with or without us. If the ultimate fate of the universe is that of heat death, then the spread of life (or lack thereof) will have no bearing on that fact. If you believe that life is not worth living then maybe you have a point: a universe with no subjects of experience would the be morally preferable to one with (paraphrasing) "virus-like" humans in it. It is rather the case that I think
your view is very human-centric in that it embraces a very particular philosophy of
deep ecology that holds nature is necessarily good and should be protected on its own terms. I think this ignores the possibility that some (many?) animals don't have lives worth living in the first place. Brains and the experiences associated with the minds they give rise to are merely survival organs for genes, after all, so the subjective pleasantness of a given organism's life is a bit besides the point, evolutionarily speaking.
Suppose, for example, that the speed of light is actually a hard limit that can never be broken. All interstellar travel would take decades if not hundreds or thousands of year.
And suppose that there is no space drive. All that can be done is rockets that push spacecraft into and out of orbits, much as we did for the moon missions.
Life would be completely constrained to the star system where it developed.
I consider it extremely unlikely interstellar travel would pose an insurmountable engineering challenge. Hell, a lot of people alive today
might live to see images brought back from Alpha Centauri from an interstellar probe. Travel would be many orders of magnitude harder but currently known physics should allow for practicable travel times.