GarryB wrote:At one point the earth had a molten surface too...
But not for around 3.8 billion years.
At least once in its recent geological history the earth was an iceball where temperatures dropped out of control and the surface was covered in ice which reflected away heat and further cooled the planet in a runaway cycle... pretty much the opposite to Venus and its runaway heating problem.
I would question "out of control." The ice ages affected only higher/middle latitudes. Plenty of thermophilic creatures like crocs survived, albeit in a reduced area closer the equator than before or since.
The first bacteria on venus could simply convert CO2 into O2... the opposite of the green house effect... get rid of all that CO2 and the clouds thin and IR radiation can escape into space... as the air cools liquid water will form seas and oceans and life becomes much more viable... it would certainly be hotter than earth but not necessarily a desert.
Life predated the oxygen poisoners, which off the top of my head appeared around 2 billion years ago. If life got started around the same time on Venus--c 3.7 billion years ago--and developed at the same pace, I'm not sure it would've survived long enough to obviate/mitigate a runaway greenhouse effect.