Varieties of criticism
Conservative criticism has nothing much to do with "left-wing" or "right-wing", because left-wing people are often very conservative, in the defined sense, while right-wing people can also be very radical, in the defined sense. The difference between "radical" and "conservative" has more to do with the belief in whether "a change to something genuinely new" is really possible and necessary. Radicals typically believe strongly that such change is highly desirable and necessary, and that it can be achieved. Their criticism is that there is "not enough" change. Conservative critics, by contrast, are very skeptical about any such change, because they feel the change is really "just another form" of something that already exists.
Vast right-wing conspiracy
In Krugman's view, the network of foundations that fund conservative scholarship, the national and regional think tanks and advocacy groups, talk radio media outlets, and conservative law firms through which they pushed their agenda to move the Republican Party to the right, far surpass in funding, size, inter-connectedness or influence anything the Democratic Party or the American liberal movement have at their disposal.