In liquid fuelled rockets, the combustion chamber pressures are limited only by material limitations and the pressure your fuel/oxy pumps can deliver. Thus, the chamber pressure can be high, and so can the thrust.
Exactly, and the oxidizer pump performs exactly the same function as a gas turbine's compressor. Without pressure in the rocket's chamber, there is no thrust. And without a fuel pump supplying a like pressure, fuel would never flow into the pressurized rocket chamber.