Modern cable systems are more akin to satellite broadcast systems than they are to the terrestrial broadcast systems of yore. There's an order of magnitude more

Modern cable systems are more akin to satellite broadcast systems than they are to the terrestrial broadcast systems of yore. There's an order of magnitude more content on cable these days. When you tune a channel now, instead of simply tuning to a frequency and demodulating the signal, content is spread across many frequencies, each of which carries a QAM-modulated MPEG transport stream that carries many programs. It takes longer to tune QAM than baseband analog or even PSK. So the physical frequency change takes longer than it used to do. Once frequency is tuned, decoder may need to check provisioning in order to be able to decrypt whatever program you've requested, so that adds to the time it takes.