I'll use Thunderbolt 3 as the example because it's the most stringent. At the 40G signalling it uses the connector loss is extremely high. The maximum passive cable you can have is << 1 m before the rx will start to encounter bit-errors. This forces manufactures to put re-drivers in the ends of the cable to boost the signal, which is obviously expensive.
Even just USB-C charging cables that need high-voltage have chips in each end to negotiate the correct protocol for both the devices and the cable.
I'll use Thunderbolt 3 as the example because it's the most stringent. At the 40G signalling it uses the connector loss is extremely high. The maximum passive cable you can have is << 1 m before the rx will start to encounter bit-errors. This forces manufactures to put re-drivers in the ends of the cable to boost the signal, which is obviously expensive.
Even just USB-C charging cables that need high-voltage have chips in each end to negotiate the correct protocol for both the devices and the cable.