Commercial software is mostly to solve real world problems. Real world problems can change very quickly and as such, software changes too.
Sure constantly changing in the complete opposite direction is probably a sign of something wrong, but changes are inevitable and we can’t expect to reinvent the wheel or start a new project as you say when you can potentially reuse what you already have.
Sure constantly changing in the complete opposite direction is probably a sign of something wrong, but changes are inevitable and we can’t expect to reinvent the wheel or start a new project as you say when you can potentially reuse what you already have.