Lintott writes in The Constitution of the Roman Republic:

It is preferable in my view, to treat the increase in magistracies [any executive/judicial position such as consul, praetor, tribune etc] at its face value - an indication that, as the Republic went on, the Romans became subject to more government. It remains true, however, that this increase in government did not add to the authority of the supreme magistrates in the city [Rome].

Moreover, the growth of Roman military power and empire, which ultimately allowed a single Roman commander discretion over territory which in the present day forms more than one nation-state, made the powers of a consul in Rome insignificant compared with those of a consul or proconsul abroad.

Which is an important point in my opinion of the ongoing civil wars in the later republic as consuls, such as Sulla, Pompey, Caesar etc could camp an army in Gaul, and draw upon all the resources of the western empire, while directly threatening Rome. When Caesar crossed the Rubicon, Pompey's strategic decision to remove all republican/loyalist troops to Greece and Macedonia, while popularly and morally crippling, was strategically sensible as it meant he would have the eastern Roman empire to draw upon - in troops, resources and money through taxes.

Part of the destabilisation of Rome may have been the increased power the ever-growing in size provinces gave consuls over the central government in Rome.