Even 20 years ago, sometimes you had to throw the truck away when the transmission failed. The C6 and TH400 weren’t the cheapest transmissions to rebuild.
On the other hand, your assertion that if the ‘expensive transmission fails you have to throw the entire truck away’ doesn’t hold water any more or less than it did 20 years ago. 2006 and 2007 trucks that have their transmissions fail today will have their transmissions repaired. The 6 speed TorqShifts from Ford are getting rebuilt and are definitely not throwaway. The same goes for GM and Dodge. However, the manuals they put in those trucks did need rebuilds, sometimes sooner than the automatics. And the history of truck manuals from the 80s forward wasn’t the best either. Look at what happened with the Ford M5OD and M5OD-HD. If you’re into Jeeps, look at the craptacular manual offerings they had: http://www.fourwheeler.com/how-to/1311-manual-meltdowns-jeep-transmissions-we-love-to-hate/
Manual does *not* mean “will last forever’ and there’s lots of people who can present evidence to the contrary of your assertion.
It's a racket where manufactures are creating a throw away vehicle with planned obsolescence. Hell you cannot even easily check the fluid level THERE IS NO DIPSTICK anymore.
What they want is for you to buy the vehicle with no recommend service on the trans for 100K. They design the trans to last 100K on the factory fluid. After 100K it is a crap shoot. You may get 50K more or maybe not. It is BS if you ask me.