It depends on the controlling authority for individual utilities what will be their policies. Most local utilities are government-controlled affairs that get caught up in whatever public/private boosterism prevails in the local political scene. "Pro-business" policies usually include some incentives for locating your business in a particular city or county. And part of that may be a sweetheart deal when it comes to utility hookups (which inevitably leads to costs being passed somewhere else). These policies typically were not enacted with datacentres in mind. Datacentres rarely employ many humans these days (at least not local to the datacentre itself), meaning that economic/wage growth doesn't necessarily follow their construction. And yet, local politicians are still greenlighting these things wherever they can, utilizing the same public/private mechanisms used for other types of businesses.
Yes, theoretically, local utilities could start charging more money to datacentres for hookups and/or capacity expansion. No, it's not likely to happen. At least not until politicians start representing their constituents.