"First build a radio receiver" means you don't have to pack anything like your whole civilization into the seed, unless you're in some kind of lifeboat emergenc

"First build a radio receiver" means you don't have to pack anything like your whole civilization into the seed, unless you're in some kind of lifeboat emergency like a war or supernova. Biology is an existence proof of universal-enough constructors (and a radio is simple compared to a tree). These existing constructors may seem absurdly hyper-advanced compared to current human technology, but I think that's a prejudice. Even current computers are hyper-advanced over the ones of just a lifetime ago. It's hard to plausibly avoid that level of progress over a few lifetimes more, short of somehow stopping progress cold.