Businesses are able to afford this luxury of starting exactly when they wish because they are able to externalize the negatives of it... forcing the employees and road providing governments to take up the slack and suffer the costs. If everyone is taking self-driving taxis, it becomes easier for employees to negotiate that travel expense into the pocket of the employer. Costs should be borne by those making the decisions, else the invisible hand can not do productive work and this economic system has much less rational basis for being the one we choose.