Probably the best way to explain about liver scarring is to show you some more pictures.
Although it doesn't look like it, the liver has a sort of tiny skeleton that can be seen under the microscope. On the top / left is a close up picture of a normal liver skeleton under the microscope - the black lines are the skeleton, and between them lie the liver cells. When the liver becomes scarred the skeleton becomes much thicker, squeezing the liver cells until they can no longer work properly. On the bottom / right is a picture of a scarred liver
You can see that the liver skeleton is much thicker and is starting to squeeze the liver cells. This degree of damage can develop after as little as 2 or 3 years of very heavy drinking (8 or more units daily), or after 10 or so years of moderately heavy drinking (5 or 6 units daily). At this stage if the patient stops drinking or even cuts down to safe levels of alcohol intake then the liver may be able to keep working.
If the drinking continues then after a few more years the liver looks like this.
The circles have been drawn around the tiny bits of liver that can still work - the rest is just scar tissue. When the liver gets to this stage there is very little that can be done short of a liver transplant.