Her evidence for this? The referendum was dominated by immigration. Leavers say it motivated their vote. Even most Remainers want it cut.
All of which is right. But none of it supports interpretation of #EUref as endorsement for a less-prosperity-for-lower immigration exchange.
In August, eg, YouGov found 62% would prefer no cut in income & current EU immigration to ANY less-income-for-lower immigration trade.
Also: this poll from last week. 48% want no/soft Brexit. 39% want hard Brexit, ie are willing to risk economic hit for an end to FoM.
There are counter-arguments, eg people more protective of past gains than future ones. And hard Brexit was always more likely than soft.