OTTAWA—The federal Liberals are betting that billions more in debt will pay for itself with the economic growth fuelled by helping thousands of workers find jobs and small businesses adapt to shifting consumer behaviour. The government’s budget estimates its spending plan will create or maintain some 330,000 jobs next year and add about two percentage points to economic growth, part of a three-year boost from $101.4 billion in new spending over that time. The largest contributor is almost $30 billion over five years to drive down fees in licensed daycares with the goal of reaching $10 a day by 2026. That money is on top of already planned child-care spending. There is also more money for broadband infrastructure and $7 billion in cash, financing and advice to help companies adopt and invest in new technologies, which is intended to address ongoing concerns about the country’s productivity gap. All that extra …