The are lots of limits on the vehicles, including voltage limits, thermal limits, heat dissipation limits, current saturation limits, etc. especially including performance limits on various components used throughout the power chain. The power chain was designed with a given performance goal, and components were individually selected that support that goal, with the assurance that each component either meets or exceeds the requirements upon it. The supply chain may have mixed equivalent components from different manufacturers, some of which met its requirements and others exceeding them. Later, when one wishes to change the performance goal with the existing components, one must carefully determine whether each component can support the higher goal. This requires careful testing and proving before unleashing the change.
I am kind of distressed at the way that many people on these forums tend to fall into an anti-corporate conspiracy mentality that Tesla is not acting in good faith and deliberately withholding performance arbitrarily from certain classes of owners. The are very good engineering reasons to go carefully and deliberately, and reasons that some cars can support a change of performance and some cannot.
