Not always, let’s say you have two options A and B that have similar lifetime costs including both capital costs and maintenance costs. A is unsustainable, but you have already paid the capital costs.

Now switching to B means paying those capital costs. However, equipment has a finite lifespan so if you time the transition to the point when you need to replace A anyway it’s essentially free.

At the consumer level electric cars are a reasonable approximation of this. For many people, TCO is about the same, but switching early is a poor choice. Similarly, for electric companies wind and solar are unlikely to outcompete existing coal power plants, but it can cheaply replace yet to be constructed coal power plants.