Einstein Rejected The Cosmological Constant.

He introduced it to maintain the assumption of a static universe, which was the conventional assumption at the time. Once cosmological expansion was observed he was delighted to get rid of the CC because it sullied GR, in his opinion.

But the conclusion of the piece is correct. The answer to the Dark Energy mystery will only come through empirical efforts. Solving the Dark Matter enigma will probably be a necessary first step. Cosmology is anything but settled science.