They actually need it because the demand is higher than expected from consumers. And because they need a moat since every big corporation trying to capture that market too, they need the moat for the biggest compute and energy they can get.
Also businesses is were the money at, not regular consumers (especially tech-savvy folk who run models locally).
If the average user gets convinced they could run LLMs for cheap at home, you cannot trap users in your walled garden anymore.