As someone who sometimes has spotty internet service, steam games work just fine when steam is in offline mode. I share the frustration of needing to update a game before playing it, but that actually can be prevented on a per-game basis, and obviously doesn't happen if running in offline mode.
Steam has offline mode which does not require internet connection. You still may not be able to play the game if the game itself requires an internet connection, but that has nothing to do with Steam.
1. Download Steam client
2. Click to install Steam client
3. Steam client starts to download even more crap itself
4. Steam client actually starts installing
5. Sign In/Register
Then when you want to install or even play a game...
1. Launch Steam
2. [UPDATING STEAM, PLEASE WAIT]... Jesus Christ...
3. Sign In/Register
4. Click to install game
5. Launch game
6. [CHECKING FOR UPDATES, PLEASE WAIT]...
7. Finally play game
And if your internet connection goes offline? Enjoy, you're fucked.
Yeah, fuck Steam and all similar bloatware.