Without the support of exchanges who could figure out how to use the eth wallet, I think ethereum would have had a hard time gaining much traction. Most of the eth speculators seem to hold their ether on exchanges. This happens with plenty of other cryptos too, of course, but the problem was so profound that it seemed that many eth holders never transferred funds to their own wallets.
This actually forced us to change how we handled customers paying with ether: originally we used the "memo" method because ethereum really wants you to have a single address (similar to bitshares, although it's just a long ugly address instead of a name), but many exchanges didn't allow users to include memos on withdrawals, so we had to make custom modifications to the wallet to allow us to create new unique addresses that customers could send their ether to using their exchange accounts. This is more complicated than it sounds, because we then have to send some "gas" to that new address after the customer makes a deposit if they pay in some other token than ether (e.g. dgd or dao) in order to move the funds from the unique address to our primary address where we can spend it (there's no easy way to spend from multiple addresses automatically). All-in-all, it's a major pain.
And don't even get me started on their cli wallets...