I think describing how I play the game might help. I build a deck, use it in practice until I think I have the core bronze cards are sorted, then look for golds and silvers to enhance it. If I think I have a decent deck, I take it into casual and plug away, hoping to win 50% and expecting 25%, tweaking along the way. I expect to get enjoyment from discovering interesting combos and trying different decks, and think that this should allow me to win a decent amount of time on casual. The issue is that other people just want to win, and my tactics are clearly inferior to milling and netdecking because silvers and golds really help poorly optimized decks that I end up using a fair amount of the time.
I fall to playing casual before a deck is complete because of the progress towards kegs, often just happy to win a single round. It doesn't help that practice mode is very one dimensional, sometimes playing the exact same cards in the same way, and has no selectable options. If practice had rewards after any number of games, it would help, even though the AI and decks are transparent and boring to play against. This problem is worse because I'm not going to buy kegs for their current price unless they have guaranteed rewards of some sort. I gladly bought the starter package.
I should point out that I played the closed beta a fair amount, and I don't think CDPR wants this to be my experience, judging by the boost to starting cards, bronze cards in general, and the removal of gold immunity. Also, if someone plays the stock golds and silvers, with my closed beta experience, I generally take them out, but then here comes a gold and silver weather deck that I don't have nearly enough flexibility in my deck or outright skill to fight.
After my last post, I decided to step up my game, look at netdecks a bit, and added witchers to give deck thinning and make a hybrid swarm deck on top of my consume, a pretty strong bronze setup. This has been much more effective, but I think it is a pretty fine distinction for a new player around level 12 to have to make to be successful against netdecks.
I know that most of these issues will iron out once I get around level 30, get kegs from season rewards, and I settle on which decks I want to mill, but at this level, running into obstacles that I don't think will be alleviated with just buying 10 kegs, results in a lot of frustration.
Disallowing milling until a very high level would solve the early netdecking, but it would create a bunch of other problems such as lack of deck variety, and - even worse - look like like a blatant cash grab.