When and why were the first Battlestars built?

oh yeah, they had space travel for all those years (centuries? millennia?) and haven’t figured out a way to cure cancer? to communicate by some more sophisticated method than radio? they know how to make nuclear missiles but can’t assemble a nuclear reactor that would keep their ship running when they ran out of Tyllium fuel?
They created the CYLONS, high-end cybernetic beings, but they can’t program a computer to network with another computer without instantly catching a virus?

They may have cured lots of cancers, just not the ones we’ve seen them talk about.

We’ve seen some evidence of FTL communication. In the miniseries they had reports from all the colonies, which would imply FTL comm. And Adama sent a fleet wide broadcast.
But some equivalent of radio is still going to be your best bet close range.

I suspect they do have nuclear engines in there somewhere… the Tylium is just for reaction mass and or secondary needs.

They got stuck with a big Microsoft contract early in the colonies and its just bureaucratic inertia keeping them there…

I think each time they settled a world or colony, they in effect had to start over. They would begin with what ever technology they brought with them, but they wouldnt have the benefit of a huge solidly established society ready to make the next technological advancement. Instead they would have to try and build the society back up and advancements would only come later on after they were reestablished.

Also cancer is nothing more than toxic mutation of cells that can occure as a result of exposure to many things and Im sure the colonies have had their share of exposure to poor conditions like we do today.

For all we know, tyllium reactors might be more powerfull than nuclear reactors.

The cylons clearly had superior programming.