I have similar thoughts about spending a lot on a tank lately - the 50gal cube hasn't been cheap.
But, IMO you have the right idea. A certain amount of expenditure is necessary to get good base equipment, good LR and decent livestock, but the day-in-day-out testing, water chemistry adjusting, feeding and watching the tank is a good deal more important. Most that have been in the hobby can confirm that spending lots and lots of dough doesn't guarantee you good results unless you use all of that expenditure correctly.
My 50 gal is a good example - I have nearly $1200 worth of LED lighting over the top of it when the 2 Vega fixtures, AI extension rail mounts and AI extension rails are counted together. But it remains to be seen whether I will get as good a result out of this than my other option - install my old-school IceCap 660 ballast, 4 T-12 VHO bulbs and a 175W Metal Halide over the tank. I'm certain that set-up will work, because it has on multiple previous tanks.
But the energy usage was huge, and it was an absolute necessity to run a chiller on the tank during the summer months. I'm hoping that $1200 investment pays off in less heat, bulb changes, less equipment to service, and decent coral growth.
We'll see.