I've long held the same view. Concatinating a couple of my recent messages:
I tend to think of the ideological spectrum as a circle rather than a line. The political center (where Reagan or Dubya belong!) would be at the bottom and middle of the circle. The bottom part of the circle might be called the region of "Liberalism" (in the classical sense of the term), and the top part could be called the region of "Absolutism" or "Totalitarianism". Instead of infinitely diverging, left and right actually begin to converge and eventually meet at the extremes, at the top of the circle.I'd say the common element among the extreme right and left is utopianism, and the nihilistic hatred of the real world, and the paranoiac attitude toward it, that results from utopianism. Extremists of either ilk basically believe that justice and liberty can only be realized in the utopia. Human freedom doesn't exist and can't exist in the real world. Any apparent human freedom is a sham, often an intentional one perpetrated by the "conspiracy," the "government," the Jews, etc, and their willing or hapless "shills" and "dupes".
At the far extremes there isn't much practical difference between left and right. The main differences are literally impractical, in that they have to do with the nature of a proposed utopia that will never exist anyway.
Whether the utopia is the socialist paradise, or the absence of all government, or the perfectly libertarian republic, or the establishment of the global caliphate under sharia law, whether it's a figment of the "right" or of the "left," really doesn't matter, because the utopia will never exist and never has. The common element is that the real world stands in the way of the utopia, and so must be destroyed, and all of its institutions discredited.
The two axes are government authority - from totalitarian to libertarian, and economic authority - from command-driven to lassiez-faire.