It's a very good question. The fact that the lib-dems were weakened during that process and sidelined is testimony to the fact that the government in place began to act as if it were a one-party government. In effect, you can have a coalition government, but you can have a system in which the dominant party really dominates.
The fact that every government that experiences a coalition in the Westminster system tries to extricate itself as quickly as it can from this "unnatural situation", as viewed in their eyes, is testimony to the fact that they're unnatural from that perspective. I don't think that specific juncture in history demonstrates too much.