In a situation where a land owner has more land than solar, and the land is already hooked up to the grid, and permissions etc are relatively cheap, and the lim

In a situation where a land owner has more land than solar, and the land is already hooked up to the grid, and permissions etc are relatively cheap, and the limiting factor is the cash to install new panels, then yes, it makes sense to build a second new farm rather than replace the old. Most situations aren't like that though. If you have limited land, it makes sense to make it more productive, if you need to spend significant amounts to set up a new farm over and above the raw panels, it makes sense to reuse what you already have.