My guess is it will get worse. Jonathan Kent is Superboy in the comics. Jordan doesn't exist. Now Jonathan has powers, which I'm thinking means Jordan may not survive the series.

The "production costs" are almost certainly largely due to actor salaries that grow over the course of a long running series. Fourteen years probably has a lot of raises. Even with a reported 25% pay cut for this last season, they are probably still high enough that it is likely cheaper to go with another show. I doubt it has a great deal to do with the actor and writer's strikes other than perhaps it added additional costs for the actors and writers beyond their salaries (like increased residuals) that they are now adding into the cost equation. The actors may be worth the extra pay (or continued pay) in our view but if they can't get the additional advertising to it (or increased streaming subscription fees as the case may be), they're going to pull the plug in favor of something more profitable. Then, 30-40 years from now, they'll revisit the well and do a reboot starring Jay Hernandez as Commissioner Reagan.

Did they? Magic can penetrate his invulnerability so in that respect it is a weakness. But, that issue aside, it's still potentially bad writing. Superman doesn't need any more powers than he already has so unless they create real consequences to its use, this sets a very bad precedent. They might have overdone it a little in the 1980s but there was a reason they depowered him a good deal in the 1986 reboot following Crisis on Infinite Earths. When characters get too OP, they can get boring and difficult to write copelling stories about. If Superman wields magic in addition to an already wide array of super powers, just what kind of situation becomes a dire situation for him? Superman can operate and think at super speed and has super senses which, unless it's by virtue of a spell, most magic s do not have. It doesn't level a playing field for him against most magic s, it largely demolishes it. That's not good if you're trying to write a compelling story.