I think it’s important to note that this system is quite different from OP’s country, Germany. And it’s also important for Americans to understand these differences.

In the US, you vote for single candidates for Congress to represent your district. In the lower chamber (“House”) the districts are pretty small, and cover about 700,000 people*. In the upper chamber (“Senate”) there are two Senators that both cover an entire state. The single candidate with the most votes wins the seat.

In Germany, part of the parliament is elected in a similar way to the US, but the other part is very different. You vote for a party, and the seats in parliament are distributed proportionally to the percentage vote across the whole nation.

The German system has provisions to ensure that parliament is roughly proportional to the total popular vote for parties. The US has no such system, and without it, game theory demands that only two parties can be competitive.