My observation is that right now AI coding agents lean towards re-implementing everything from the ground up. This of course will not scale. It will scale beyond what humans writing code would scale to, but we will ask the AI for more, so it will even things out.
1. We will develop new programming languages that are AI first, in that they are aimed at readability and comprehensibility by machines
2. We will adapt our working style (e.g. how we prompt and train the AIs) to factor in maintenance cost.
i.e. AI first implementations will go through the evolution we had with human based code development.
There's a funny trick where if you are an experienced software developer, and take time to think about your design and describe what you want in clear terms, it will actually do things your way. Weirdly, this still saves massive amounts of time.
People who don't understand how to build good software LOVE to expound on the things we'll have to design in order to make AI tools "lean toward" building better software.
It seems that these folks are not willing or able to conceive of, you know, actually getting good at this stuff.
For this reason, it never occurs to them that human beings are STILL the source of the best ideas and designs.