Optimistic? That is quite pessimistic, by a couple of zeros.
Anthropocentric argumentation is flawed. But you can estimate chances for life by numbers that do not depend on our existence. Scientists estimate that there are about 300 000 000 planets in the habitable zone around planets in our galaxy. They exist whether or not we do. Give or take a zero, does not matter.
There are lab experiments that try to simulate conditions on early earth. If you mix the the chemicals and stir, you get small lipid bubbles and amino acids. And they only mixed it obviously for less than hundred years and not for 100 000 000 years. If you can get cells from the makeup of chemicals, you will get cells. It is Murphys Law backward. Abiogenesis occurs because it can.
People do not intuitivly grasp big numbers and chances. In the visible-to-us universe, there are about 10 000 000 000 000 000 000 planets that are in a place around their star to have conditions that allow life as we know it.
One could shift the goal post and speculate, we might be the first techno civilisation in our galaxy. The need for heavier than hydrogen elements certainly limits possible life for the first 10 billion or so years.
Probably we will be the aliens invading other planets.