Yes, that's why I'm phrasing it more like a hypothetical 2x - because it's not 2x in practice. In essence, a 2MB with segwit is actually >3MB without - from the numbers they are giving.
I think you are missing an important point in that segwit is not (in itself) about scaling - the 1.6x space saving is a side effect - its about removing malleability* bugs in scripts so that complex contracts ( for payment channels) will work. At present most of the script functionality has been removed/disabled due to malleability.
Thinking that segwit is part of the immediate capacity issue is wrong. These are long term developments to support bitcoin in the future. But they are being rushed through now under the guise of 'scaling'. Dont get me wrong - I like segwit - but it needs to be introduced in the correct context, with the correct due diligence.
* but tragiically still fails to address all of them....