Even the 75K is super optimistic. If you are touring you want to bring your own equipment, much easier to run a show that is roughly the same in multiple places then relying on the house rig in multiple venues. Once you factor in bringing your own gear (Almost definitely rented, sound is expensive, lighting even more so), you now need to factor in maintenance of the equipment and rigging.

Also the assumption you can get one guy to do lighting and sound is pretty unrealistic unless your show consists of a static wash throughout the entire show. Theatrical shows you can get away with it, but that's usually because the man hours are heavily front loaded into pre-production, but with live music you will need a dedicated LX Tech and a dedicated Sound Engineer.

I moonlight as a lighting technician during the evenings and weekends, mainly working in handful small local venues, there's me running lighting and the sound engineer doing his thing. The bands playing are easily spending £300 a night just on 2 people (And this is a small venue probably about 200 cap in the main hall), youd be spending much more for a touring crew