I really don't worry about it myself and just fit the tables to the screen as best I can and live with it, but as a little number crunching exercise:
So, 16:9 is a ratio of 1.78 to 1
for comparison
- a 70s em is around 2.02 to 1,
- WPC standard around 2.24 to 1,
- modern Stern standard 2.07 to 1,
- Data East standard 2.27 to 1
now here is where it gets interesting.
- a Gottlieb system 80 widebody is 1.96 to 1
- a WPC "superpin" is 1.98 to 1
- a Stern widebody is 1.88 to 1
- a WMS system 1-11 widebody is 1.56 to 1
- Data East widebody 1.98 to 1
so really the widebody tables are actually much closer to the screen ratio of our monitors than the standard tables, and to get them right the standard tables really should have pretty decent black bars on both sides and most wide bodies smaller black bars. Now given that we usually put some sort of inclination on them, especially newer tables with ramps and toys and such, the whole thing is somewhat skewed.
Others do things like creep the apron off the bottom of the screen and scrunch the top arch off the screen as well to get it closer.
so there is my 2 cents, do with it what you will 
*All numbers calculated from VP Dimensions Manager