The reality is that Bitcoin will never get mainstream adoption without easy to use online wallets.
Obviously there is a trust issue in the market now but nothing that the market can't solve going forward.
And we have another problem with the mainstream adoption. When I pay to another address some coins, that transaction may take at least 10 minutes to get over.
Online wallets must also resolve this issue.
That's where green wallets kick in i.e. the online wallets send their payments via one of their central wallets so people know (from experience, reputation) that the payment is real even if it still needs to get confirmed.