The Big Bang model of cosmological history is one of the most exquisitely tested ideas in science. Just for starters, any competing model would need to duplicat

The Big Bang model of cosmological history is one of the most exquisitely tested ideas in science. Just for starters, any competing model would need to duplicate the highly sensitive predictions of Big Bang Nucleosynthesis (https://en.wikipedia.org/wiki/Big_Bang_nucleosynthesis https://en.wikipedia.org/wiki/Big_Bang_nucleosynthesis), the results of detailed simulations of structure formation (https://en.wikipedia.org/wiki/Structure_formation https://en.wikipedia.org/wiki/Structure_formation), and the existence of the cosmic microwave background (https://en.wikipedia.org/wiki/Cosmic_microwave_background https://en.wikipedia.org/wiki/Cosmic_microwave_background) (and at this point it would probably need to match the detailed spectrum of the CMB at least as well as inflationary models do). That's not an impossible task, but it's an awfully high bar: the widely accepted "Lambda-CDM" model (a specific Big Bang scenario involving both dark energy and cold dark matter) and its parameters have proven to be amazingly consistent under a whole bunch of very different observational tests. The odds that it has passed all of those tests so very consistently purely by dumb luck, while the universe actually follows some entirely incompatible set of rules and history, seem vanishingly small.