When airplanes had no electrical systems, they had no electrical equipment.
Simpler times. Then airplanes began to have lights and radios and electric starters. Next came avionics and panel-mounted GPS units. Newer airplanes even have USB ports to power the electronic items that aren’t installed in the airplane, such as cellphones and tablets.
When the electrical system became an integral part of an airplane’s design, engineers wisely decided that the engine would operate independently of that system. Thus, a piston engine’s internal combustion keeps it going long after anything electrical has given up on you.
In day VFR conditions, an electrical failure isn’t really an emergency. You’ve still got a running engine, fuel, a wet compass, an airspeed indicator, a vertical speed indicator, an altimeter—and your eyes. Fly the airplane and find your way to your home base or another suitable airport.
Electrical failures in airplanes with all-glass avionics aren’t any more or less common than airplanes with analog instruments. You’ll need backup navigation tools, such as charts or a tablet or smartphone loaded with flight planning software.
A handheld radio is an inexpensive and lightweight addition to your flight bag that you can use to contact a control tower in the event of a radio malfunction. Ensure the handheld has charged batteries. Its range will vary, but you can expect 5 to 10 miles. An external radio antenna is the key to extending the range of a handheld radio. Some manufacturers claim readability up to 25 miles. And sometimes cell phones can be used to call ATC in flight. Otherwise, follow standard light gun signals to land at a towered airport.