More station staff would be available if they were paid less. London Underground (where station staff have many roles and are highly paid) had a number of station staff shortages some time ago. London Overground and other national rail operators in Greater London have lots of underpaid agency staff hanging around doing not much. I'm sure a happy medium could be found.
Another option, again exercised by London Underground, is to reduce or close ticket office hours. These staff can then be redeployed to ticket gatelines. Unattended gatelines are already in common use too where they're at a secondary entrance, and the staff are at the primary one. Finally, a useful layout cam be to have the ticket office window immediately alongside the gateline at small stations, so one person can serve customers at the window and also, bu turning sideways, customers at the gateline.
At the moment though a lot of this is worry about nothing. Passenger numbers are so low that fare evasion isn't costing as much as it would have been previously. A certain low level of fare evasion is likely always to be tolerated by the operators, it's just nore expensive than it's worth trying to get compliance above 98%. The thread title is slightly misleading - ticket inspection was never suspended, it was just reduced for a while, is increasing again and is more likely to be taking place at a station than on a train.