Never is a long time.

What usually happens is, a government collections agency tries to collect on behalf of the victim and forwards any money they manage to get. Because this is a government service funded by taxpayers, the collection process doesn't cost anything for the victim. They will check for any assets such as property, vehicles, bank accounts etc in the convict's name and collect from that if possible unless the convict pays within a certain time.

If this fails because there are no assets, and if there's no current income to garnish, they put collections on hold until such time as there is something. If/when the thief gets a job or receives other income (including welfare), they'll start collecting by garnishing the wages. They don't take so much that the convict has nothing left to live on, however, as that would only force them to commit more crimes.

The statute on such collection doesn't run out until 10 years and can be extended, extensions are routinely granted. So if the thief turns his life around and gets a job at some point in the future, the victim might begin to receive a trickle of reparation money long after the sentence.

As a practical matter, almost everyone has insurance so the thief ends up owing the insurance company for ever while the victim gets damages covered by insurance.