It could need to go smaller but it could need to go bigger too. Also depending on how much it's used the grinders could be getting dull. Or maybe a pre-infusion might help.
The la marzocco with the three group heads is as small as you really want to go with those. (Water tank and separate steam tank) Then it needs to be serviced.....and a water line with special filters needs to be run to it. Those machines need at least 208 volts to run. But they make great steam for the milk and never seem to run out of hot water.
In addition to the puck preparation for espresso it's a time/volume thing. That's the goal. You want a specific volume of finished espresso in a specific amount of time for a 17-22 gram dose of ground coffee.
Which is where a true barrista comes into play. He works his machine, the coffee grinders, the puck, the pressure, the water temp and then foaming the milk just right so he can make a pretty picture on the top of the cup.
A GOOD barrista can make $30/hr in a prime location coffee shop. These aren't the button pushing types of barristas Starbucks is spitting out. (The have fully automatic machines too these days).
But one with paddles or snap switches and can make pretty art on the top of the cup.