A corporation operates in their own self-interest.
A corporation that is a monopoly has no motivation to keep pricing "fair" and, in fact, has an interest in making prices as high as possible. It is never cheaper this way.
We, as a society, seek to work around the problems that naturally-occur with monopolies by regulating them.
In Ohio, most of our residents have one provider (AEP). AEP owns the local infrastructure, and they also own the transmission infrastructure, and they are pretty tightly regulated.
To help keep pricing in check, it is required by regulation that the rate at which AEP buys their electricity at is set periodically by a competitive bid process. (This is, in theory, a process that works well for consumers and provides a reasonably low price: If a supplier can buy and sell (or otherwise produce) electricity cheaper, then they can put their bid in and have an opportunity to do so.)
The problem with regulation is that it is regulates. It is inflexible.
And sometimes, this bid process goes wrong: Early in 2023, for instance, it resulted in a generation price that was set to approximately double in six months[1].
The solution to both monopolies and regulation is consumer choice in a competitive marketplace.
Obviously, we in Ohio can't usually decide whose lines and infrastructure we use -- they're monopoly-owned. There's some exceptions to this like [2][3], but broadly speaking: Of course AEP is involved, because they have to be involved.
But we do get to choose our generation supplier[4], which is probably similar in function to how folks in Texas can pick their "retail provider" (except we don't get time-dependent metering).
And that very limited aspect of consumer choice does work for me, the consumer. I was able to completely bypass the 2023 price hike by selecting a different generation supplier. In fact, my total billed price per kWh of electricity used (inclusive of distribution, transmission, and fees) was actually slightly reduced compared to what I had been paying previously.
It's not a perfect system, as there are no perfect systems. But this little sliver of competition is better than being completely beholden to either an unregulated absolute monopoly or an inflexibly-regulated absolute monopoly.
[1]: https://puco.ohio.gov/utilities/electricity/resources/histor...
[2]: https://clydeohio.org/159/Clyde-Light-Power
[3]: https://www.columbus.gov/utilities/about/The-Division-of-Pow...
[4]: https://www.energychoice.ohio.gov/