No. You can finish some types of attics, but not all types. Some attics present major structural challenges, and some are simply not large enough to satisfy all the building code requirements to convert the attic to a living space.
An attic with roof truss framing does not usually have enough space or structural integrity to be finished unless you completely reframe the roof. This makes the project much more costly.
An attic with a pull-down hatch entrance cannot be converted to a code-compliant living space without installing permanent stairs connecting to the first floor. If you live in a very small home, a staircase may take up too much of a footprint on the first floor.
Some attics are too small to finish to code, regardless of the roof framing. Many attics have sloped ceilings, and building codes require at least 50% of a room with sloped ceilings to have 7-foot ceiling height.