And like some one else has already stated "lost coins" aren't truly lost, we just don't care or have the technology yet to recover them.
As things are, there is no possible way of detecting "lost coins", short of asking every person and every computer in the whole world whether any apparently "lost coins" are his or hers or its.
We would need new and very different rules to determine what a lost coin is, for example, that all bitcoins have to be moved from one account to another at least once every year. Then we could state that a bitcoin that has not been moved in a year is a "lost coin".