The timevault combo is actually a 2 card combo where BOTH the cards don't do very much. Key is pretty useless in blue decks. Tezz is more useful but he costs 5 mana and at least 1 turn so he's not overwhelming on the scale of things in vintage
Key is actually pretty decent on its own - it is useful with all targetable artifact creatures for providing combat tricks, and goes with absolutely all artifacts (including itself) that have tap activated abilities (Sol Ring, Divining Top, etc.). Key isn't a house, but it definitely meshes better than Vault, as in it isn't completely useless without other direct support cards.
Yeah, dearth was the wrong word. I think the word I was looking for is extant.
Glad someone else spotted this - that was my exact same reaction - and it made me feel a bit queasy and worried about drain. There's even a bit where he says something along the lines of 'blue deck using force of will and the best engine, Mana Drain FOR NOW' - something like that (i'll edit in quote later) - anyway, it was chilling.
You obviously missed their point, which is actually a really good one.
To make Wizards point more obviously, restricting Force would be dumb because then combo would take over, and rampant first turn kills would make the format completely boring.
T1 has cards that there simply aren't enough other cards that do anything nearly the same for the same ridiculously low cost or ease of playing.
Examples are Force of Will, which has Foil, and Pact of Negation as its closest approximates, which are at once unplayable and/or ridiculously narrow.
Workshop has Ancient Tomb.
Bazaar is simply matchless - I guess the closest analogs would be Careful Study, Breakthrough, Attunement, and many other things that aren't free.
Ritual has Cabal Ritual, Rite of Flame, and Culling the Weak.
These analogs are strictly inferior.
The thing with Mana Drain is that it is a UU counter that provides slight mana acceleration, usually a drop or two at a time unless you get somebody who walks right into it.
If drain were restricted, it's not like there wouldn't be 3 other UU or 1U counters (like Counterspell, Mana Leak, and *insert counter here*) that could be dropped right into the open slots. Combo/Control deckbuilders would just have to bring the curve of their decks down to accommodate for reduced mana acceleration.
That said, Drain doesn't appear broken enough yet to warrant restriction, and it is ostensibly an interactive/reactive card that provides situational mana acceleration, of which nothing analogous currently populate the B/R list.
That said, anybody who bemoans restrictions and threatens to leave the game - you are free to play whatever cards you want casually. If you are into the sanctioned tournament scene, then you should be happy that your format isn't allowed to stagnate. For every person who bemoans restrictions, there is another who thinks it is exciting because it enforces a complete remapping of the meta.