Valve and Bethesda are major developers with many things in common, the most notable being that they both make great games, that they are silent as a tomb until they have something they want to say, and that they will take as long as they please between games.
 
It is frustrating for the fan, waiting to hear news of a new project of follow up for sometimes years of radio silence.
 
They must make a fair amount of money to spend so much time cloistered in development between major releases.  Not being owned and micro-managed by EA, Activision, or the like probably helps too.
 
One could go mad reading the enthusiest forums for these developers; the nit-picking and fantasy parsing of every tidbit of communication from the studio, the holy-war-furor of the flame battles between factions of fans who believe a particular portent means an announcement will come soon, and those who interpret it to mean the project has been candled.  The spread and mutation of misinformation is doubly vexing as it erodes the value of the few facts that exist.

If you've been looking for word of Episode 3, or the next Elder Scrolls game, or even the next "Meet the" video, you have probably at least seen the edge of this information abyss, and I recommend if possible to avoid taking the plunge.

On the Bethsoft forums, they are on thread (THREAD, not page) 34 of TES 5 speculation.  People are trawling patent filings held by Bethesda for clues, getting into legal debates about copyright expiry and proof of commercial use.  It is madness, and sadly, it has taken me in.

The secretive nature of these companies provide them several benefits, but boy is it hard on the fans.

one could argue that bethesda does not in fact make great games, but I see your point.
 
I wonder what's more likely; episode 3 (or HL3 if they do that) or TES 5 first.

Zityz:  Yeah, Zenimax is a company that owns: Zenimax Online Studios (from which we may someday see an MMO), Bethesda Softworks (who have published dreck like Rogue Warrior and Wet), and Bethesda Game Studios (the development wing responsible for The Elder Scrolls and Fallout 3).
 
The development side of Bethsoft only puts out about one game every four years.  Thats a pretty lengthly period between returns on capital invested in development.  
 
Laketown:  If you're confusing the crappy games published by Bethesda for games they make, you might be in error.  If you are amoung the players who just don't enjoy  their brand of action/rpg that is a matter of taste.
 
I hope E3 will shed a little light on which franchise will be updated first.  Hope, not bet.