The modern approach takes account of such unfairness. The rule is that if (1) the offeror should reasonably expect to the offeree to rely in a substantial way on the offer before acceptance, and (2) the offeree does so rely, then (3) the offer is binding as an option contract to the extent necessary to avoid injustice. See Restatement (Second) Contracts ยง 87(2).
The point of recognizing the existence of an option contract is that an offer governed by an option contract is not terminated by an attempted revocation.
To illustrate the rule, switch from Petterson v. Pattberg to a more recent case, Drennan v. Star Paving Co., 333 P.2d 757 (Cal. 1958).