so many people saying “its hard to make a modem” but nobody has anything to say about why its hard

8 years ago looking at the state of AMD, Intel, IBM, and every other CPU fab would lead some people to say “well yeah making a processor is extremely hard”, yet these days amazon and google literally make their own and there are tons of riscv startups. not saying making a modem is easy but sometimes there are other roadblocks in technology, like bad management wasting money

How can someone research so much but also completely miss basic specifications like bus width? Like really how does someone type this out and not ask themselves, ‘are these devices free to make or do they have a cost?’