He is right that the moderate left has effectively abandoned the working class, but he is wrong that they abandoned it in favor of liberal elites. The moderate left has in fact abandoned the working class, but in favour of moneyed interests, be it multimillionaires, large corporate conglomerates or banking giants. This is true of moderate left parties across all advanced economies. In the US you could rephrase it to say in favor of the lobbying class. Fundamentally, due to Reagan's administration outsized influence in US and world politics, the moderate left got infected by supply side economics from the 90s onward, later known as trickle down economics. Another way of putting it is that the Economy Overton Window moved clearly and definitely to the right.
The main consequence of this was depressing lower and middle class wages across the board, in every advanced economy since the 80s. First and foremost, over time this created an undercurrent of resentment, due to a disconnect between expected purchasing power and effective purchasing power among the traditional left-wing base. This decrease in the revenue of the general population, also inevitably led to a decrease in tax revenue, which has had a definite negative effect on all public services, especially healthcare and education.
And while this has been terrible enough during left-wing government tenures, right wing governments have been only too happy to make things even worse than left wing governments are making them.
Also, given the extended timeline under which this has been happening(30 to 40 years, depending on the country, I'd say), it's beyond the ability of any well meaning government to effectively turn this tide and significantly correct economic outcomes for working class families.
This means that we are literally in an era of economic inequality that would make late 1800s robber barons blush at even the thought of it. And the only parties that have been able to effectively profit politically from this state of affairs are far right parties, meaning parties propped up and financed by the same financial interests which are making things worse economically for those who are poorest.