I suspect we will eventually get there, but it is no way guarnanteed. Look at fission power. It was supposed to deliver power "too cheap to meter." That never happened.

Likewise cheap fusion power may never happen. It doesn't mean fusion power will not be useful. For space exploration I can see huge benefits. It can also be very useful to backup renewable energy when the sun doesn't shine and the wind doesn't blow.

But it is not given that it will make power cheaper.