Once they do, we'll even forgive and forget that all these services deliberately decided to wait - I know it's not an easy nor a simple task to port over all their systems and wallets to SW, but they should realise, the sooner they deal with the pain, the better for them in the long run. Take the losses from consolidating all that legacy dust now, while Bitcoin price is still recovering.
I'm pretty sure that services like Coinbase are deliberately sabotaging SegWit adoption to participate in pumping altcoins by keeping Bitcoin fees higher than they could have been. Coinbase and Bitpay were actively supporting SegWit2x, claiming that people will abandon Bitcoin if fees will be too high, but now that they for 5 month already have the ability to lower fees for their customers and still refuse to do so, it's clear that they don't really care about fees and their customers. And what is worse, they also don't batch their withdrawal transactions, which could have reduced fees for them by 80-90%. This perfectly demonstrates why centralized systems can't be trusted and tend to abuse their power, which is why Bitcoin was created in the first place, and we as a community should not let it slide - we should tell newcomers to stay away from Coinbase and other services that support SegWit2x or Bcash.