there it is again. why is 1500 the perfect number? any cheaper and just throw it all away. only 5% (or whatever) are using upgraded cards. we should just throw them away, too. anyway, just the first 20-30 need to be cheaper to close in that massive gap between your first deck and your first upgraded deck that scares all the casual gamers away.
once you get upgraded cards, that doesn't mean your never gonna use unupgraded cards again (just most of the time). and certainly there are interesting decks without upgrades but the question is, would people play more if they had access to more cards? and i think that it should be obvious that they would.
But the time taken to get your upgraded cards doesn't seem that long to me. With like 2 upgrades you can already get a decent FG farmer now. If your 5% includes everyone who has played elements before, I guess its obvious that many people left because they didn't like the game. If you want to attract people, use features instead of cards. Those people that come and go aren't even MOTIVATED to build decks; I think the current number of unupgraded cards is ample enough for them to start building their own decks.
1500 is definitely not perfect; its just a random number that works well. I think that people only want upgraded cards so much because they see everyone in the forum having them, and they want an easier way to get them.
And now, lets talk about why I ever came to know the game and enjoy it. I had someone to PVP with most of the time, to pit my decks against, during the unupgraded portion of the game. It was slow, but still a lot of fun building my own decks. Quests pulled me along when the game got stale, and it was a pleasant surprise when I found out I could upgrade my cards. I only started using the forum after that, noticing new decks and combinations I could try which worked better.
True, the unupgraded portion could have been made shorter. But right now, you can definitely say that the unupgraded section is used well, that the experienced players have something to occupy them. Until Zanz makes any new features for the game, the current system is working fine and dandy.