everyone gets a better grid.
If the data center which requires the grid improvements is fully paying for the upgrades, I'm OK with it. OTOH, if they expect to fob off the cost of the otherwise-optional upgrade on the rest of the ratepayers, Fck-NO!
And for those who say "but it benefits the rest of the ratepayers, so they should pay too", NO! If you (person or corp) come in and demand we change something, you should be a net benefit for everyone, not just yourself.
Be a good citizen and help everyone, and you'll find support. Don't, and find people see you as an asshat and you'll find opposition.
More importantly, what says the grid improvements will go beyond upgrading the corridor to the new data centers? Sure, that might benefit customers right along that route, but not customers in general. IOW, even the "overall" improvements are likely to be limited, but the costs will be borne by everyone.
That said, the way grids are going, I consider the right solution to be primarily off-grid solar+battery on every house, maybe with local grids to share/level excess capacity, and maximum local solar/wind+battery for commercial. That would yield a robust power system far more resistant to human disasters relevant to civil defense and natural disasters; when every house can maintain basic communications, refrigeration, and sanitation on a near-indefinite basis (which is not possible with a grid-based collapse/destruction), disasters are far more survivable.