Buyers frequently waive the inspection contingency in hot markets with limited supply. Sellers are more likely to accept offers with fewer contingencies.
You're not wrong. However, even if you make an all-cash offer and remove every single contingency, you're still looking at roughly 2 weeks minimum to close. You're making the assumption that title companies are competent (they are not) and move quickly (they do not). Wire transfer takes a few days, need to find a notary to sign all of the closing docs, and title companies are slammed with all of the other home purchases happening as well.