All the Beta cards will have a new standard version

That is not what will happen. It would destroy the prices of all cards if they print them ever again and they know that and regret their decision to keep the same cards in the Beta as in the Alpha. There will be an ENTIRE new set and no Beta card (or Alpha) that is available now will ever be printed again. All cards will be different and work on them own. But obviously people will have to get some of the old cards from the market to be able to play the best combos.