Doesn’t make much evolutionary sense on Earth where the high atmosphere is one of the least hospitable places to be. Makes more sense on Venus, where the high atmosphere is the least hellish place one can be.
We can, in the meantime, investigate strategies for collecting our own cloud-dwellers so we can build a probe that does the same on Venus while it descends a little through the atmosphere before launching back a sample recovery capsule.
Heat shield, parachute, balloon, stay for a couple hours collecting samples of the atmosphere, filtering particulates, making nice movies, and so on, then pop the balloon right before launching the return vehicle?
It’s not unreasonable to have microbial life floating around our atmosphere when you consider the fact that there is microbial life deep in the trenches of the ocean