If you are suggesting that the closed CoT's provinces then be routed to another CoT you own, this is a bad idea. People would only use it to shut down CoTs where they are facing a lot of competition, or direct trade to a CoT in the South Pacific that only three other states know about, creating a super CoT with no competition for a monopoly.
Wouldn't it defeat that idea of CoTs being reflections of focii of trade independent of government control? I mean, you don't make CoTs - why should you (would you) destroy them?
Beyond the idea of creating a super monopoly or limiting the trade of other states I can see no benefit to this, anyway. CoTs provide merchants, tarriffs and monopolies - that make more merchants.