Okay, this statement is wildly flawed. First off, NO team "banks" on a 3rd or 4th round pick (if they were then they wouldn't have waited that long to select them).
There's a reason (probably multiple reasons, actually) why the player was selected so late. No team is "banking" on them. What they're doing is hoping that they can develop them into something worthwhile (which is the case with most mid-to-late round picks). A true "fool's errand" is mortgaging your future on a guy who's not even recognized as the best QB prospect that year while your team is flawed in many other areas.
In all honesty it doesn't matter what the Rams do with all those picks from that trade. Unless RG3-13 gets the Skins a ring it won't be worth it. And right now they're far from being worth it.
Griffin already has a division title under his belt in year 1, and I expect he will be much of the 2012 version then the 2013 version in 2014.
The opportunity cost for the Rams was to stick with Bradford, or potentially trade him for a 2nd round pick and draft Griffin (Shanahan probably would have given up a 2nd rounder for Bradford in 2012)
The Rams used the picks to get 2 RBs, 1 of whom will be on special teams, 1 DT who looks like he can be a player, a troubled CB who has talent, and a left tackle they plan to move to guard. They have already released a player they drafted.
The Commanders missed out on the chance to draft anyone Janoris Jenkins/Amini Salatu/Cordy Glenn/Jonathon Martin (those were picks 39-43 in the 2012 draft), anyone from picks 22-26 in the 2013 draft (and cost probably isn't the 22nd overall pick in 2013 without the Griffin trade, the Commanders are probably picking in the top 10 again) and a potentially elite player this past season.
My guess is if the Commanders had stayed put they would have selected Tannehill and been 6-10 or 7-9 again in 2012, had another pick around 9-12 in the 2013 draft, and ended up in the same spot again in this past draft.
To judge this trade we will have to see not only how Griffin progresses (and so far he is 1 up on Bradford who never has won a division title) but what the Rams end up doing with Bradford. If in the 3 years of extra picks the Rams end up out of the playoffs each time (they are already 0 for 2 and haven't finished .500) it is going to be a loss to them as they have to figure out how to get a QB in 2015.
Meanwhile the Commanders will be set at QB with a 24 year old that has already produced a division title, and a full slate of picks going forward from 2015 on to continue to build around Griffin. The car note is paid off and the guy just turned 24 in February