Topic has reissued the majority of its back catalogue digitally.

Topic's digital reissues

You can find them on iTunes, Spotify, amazon.

It would be impracticable and would probably bankrupt them if Topic were to attempt to reissue its entire back catalogue on CD. I mean, good as those albums are, there simply aren't going to be enough purchasers of a CD reissue of a Bob Hart or Rose Murphy album to justify the expense.