Simlply in these days there are fewer transactions, it's not that all blocks need to be full.
Yep, SegWit transactions have been up to 18% of the total, and we've had many larger than 1MB blocks, but what's holding it back is sites such as Blockchain.info, Coinbase/GDAX, ShapeShift, BitPay, Poloniex, Gemini, Bitfinex, and Purse.io still, to my knowledge, haven't added SegWit receiving/deposit address support. You'd think they'd all want to do it, if only just so that they, themselves, could save on transaction fees -- not to mention being able to sell their users/customers on the ability to save on transaction fees. People should contact any of these companies about adding SegWit addresses -- if we genuinely want to help solve the problem, it's something that these businesses can already do right now.