"Ok, good arguments; isn't NASA also into R & D and therefore very tempted to apply the newly discovered software or the new technology into a program because it's so interesting and "promising"? (Transhab comes to mind; it was the the inflatable module meant for LEO, a Moonbase, a trip to Mars and a Marsbase); the problem: it came too late. Or did it? "

Yes it came too late.

"The space station was also late, but that's because (among other) of those added capabilities that had been thought of earlier and that NASA felt they should be added to the station, delaying it more."

Which is exactly why TransHab wasn't added, it would have been one more thing. TransHab was simply the "last straw that would have broken the camel's back". I think that Transhab had lot's of merit, but it was too bad NASA had screw-up previously. If NASA had performed well, Transhab would have probably been added (the added cost and time would have been considered worth it).

"The Moon program had a deadline, not the Shuttle nor ISS. That's also part of today's problems."

Yes, it definitely helps to have a reasonable deadline.

"And, let's look at the Russians: old fashioned technology, very little evolution (a new Soyuz spacecraft ready for november 2002: the only innovation is the possibility for small and tall astronauts to ride it; that's about it)."

I think this was mainly due to the shortage of funds- not so much because the Russians were particularly wise:)