Yes this is major component of what I mean by profitability. The utilities spend vast sums on grid equipment and transmission lines that they pay for over decades through bond offerings. The grid is designed to distribute electricity from centralized generation stations to distributed customers (a "mainframe" like model). They support the capital cost of this infrastructure (debt payments) and maintenance on the equipment through their per kWH rates.

An example of this is that, where I live, some depreciated hydro assets produce power at $0.0025/kWh but the electricity rate is $0.11-0.14/kWh. It is not unusual for the majority of the cost of electricity be in debt and equipment maintenance rather than generation.

If I generate electricity on my roof then the utility is screwed from both ends, they must credit me way more than it costs them to generate their own electricity, and feeding electricity into a grid not designed for it adds further wear and tear to the components. Their revenue goes down and their costs go up.

Unsurprisingly, given their sunk costs and the prospect of defaulting on huge bond obligations, they will not permit me to install a rooftop array that will generate more than 40% of my usage, even if paired with large battery systems.

This. I worked for what in our deregulated market is called a "distribution company" (owning the transmission from the HV lines to the meter at your home), and can absolutely attest to what enslavedrobot has said. The funding model for getting electricity from A to B was predicated on assumptions that you could amortize the high capital costs over multi-decades. Which is all fine until distributed generation (rooftop solar) exploded in a time-frame much smaller than expected. Tbh my personal view is that the writing was on the wall large enough for anyone with eyes willing to see to start planning accordingly, but true to form, most companies just tried resisting the change.

I thought infeed limits were all about protecting the grid from power surges; what can an enlightened utility do differently? Battery storage would double the cost of community-generated solar, so even an enlightened utility might be unprofitable taking non-dispatchable power from homeowners, no?