The key selling point of such an increase to the block size limit has always been the idea that an increase in the supply of block space will lead to lower transaction fees and the ability for the network to process more transactions per second, but the current congestion seen on the Bitcoin network has actually had a positive impact in terms of the forced optimization of companies’ interactions with the blockchain.
This was one of the original (and strongest) arguments against XT, Classic, Unlimited, et al. If we simply increased the block size every time demand warranted it, services/custodians (and users) would never optimize their transactions. They would simply get used to increasing block size instead.
This is soon going to be a non-issue, because the Lightning Network will solve all those issues. These companies can start byimplementing SegWit in preparation for the Lightning Network.
Segwit and Lightning aren't going to solve Coinbase's fractured UTXO set. And I suspect that's one of the reasons they've long supported hard forks. And we have to factor in onboarding costs as well (opening and closing channels). It's a bit early to say Lightning "will solve all those issues." On-chain transaction demand will only increase, so on-chain transaction optimization is going to remain extremely important going forward.