Bandwidth matters because spectrum is a finite commons. Digital TV required giving up bands that were in use for other things (e.g. wireless microphone systems and some ham bands) as it is, using even more bandwidth would have required even more spectrum. Other people have stakes in the spectrum for very good reasons and often much more important reasons than "I wanna watch TV". Even for satellite TV, which uses frequencies high enough that there is lots of bandwidth is limited, because using a lot of bandwidth would require new LNBs and multiswitches for all customers.
> My point is that there are many ways you could apply engineering, money, bandwidth, etc to reduce or eliminate the problem but they don't because they see it as good enough to not lose customers.
Can you name one for each category you bring up? Especially the "engineering" one would be interesting. Obviously dedicating an even huger chunk of spectrum to "I wanna watch TV" would make things easier, so that's not really interesting. And "let's just give each customer a TVoIP stream that can start immediately" is also a pretty obvious "money is no concern" (and also "we don't care about customer adoption costs") option.
We agree that there a whole series of parameters that can be traded off against each other: 1. Bandwidth required
2. Number of channels
3. CODEC complexity/engineering effort/cost for encoders and decoders
4. Iframe interval
5. Number of tuners/decoders in receiving equipment
6. Resolution
7. Frame rate
8. Video quality
So the standardization people decide how to set those, and basically channel switch time gets set to the maximum value that doesn't cause people to cancel their service.
If you want to see something pretty astonishing that can happen if you set the tradeoffs differently, check this out: https://puffer.stanford.edu/player/
My point is that there are many ways you could apply engineering, money, bandwidth, etc to reduce or eliminate the problem but they don't because they see it as good enough to not lose customers.