Progressives must surface the obstruction posed by the Democratic Party establishment. Primaries are prime time to do that, which means there is good reason for Sanders’ campaign to continue.
His program is not being attacked because of fear that he is endangering the "progressive economic agenda." Rather it is being attacked out of fear that he actually believes in it.
Technological change has not been a leading factor in our wage problems or inequality in the 2000s. Wage stagnation and growing wage inequality are the consequences of policy decisions made over the last four decades.