Hi John.
Yup! Looking at Sequoia 15, certainly covers what I would consider being a Pro program for audiovisual use but as you say, is overkill for anyone not doing seriously paid work, or happens to have more money than sense 😉. This is why I'm trying to find out at what level these productions are being aimed at and the time constraints involved. At first, I thought it was one project, then it appears to be more than one project.
As time is money, or so they say, then trying to get everything right (or as much as possible) in the take reduces time in post-production but needs more channels and equipment. If you are not so hard-pressed for time, then additional recordings can be made at the location before or after a take for specific effects, needing less equipment but more post-production time. Less available time on location and less equipment means more studio time and more post-production, but possibly has the least equipment expenditure requirement.
Programs like Sequoia are a one stop shop for editing. Possibly needing less processing power for the amount of workload as well. Used alone, they are crippled without the necessary supporting hardware which also wouldn't be cheap. Any mainly audio multichannel DAW would also need to at least be able to support one video file to edit to if it was for a final mixdown. I'm not sure about linking programs. My own personal experience would be of suffering sync problems in real time as processing requirements climb with complexity. Keeping such a project within one program is safer unless you could chain two PCs / laptops together.
All such Pro programs though are very flexible and mostly reliable. I had never heard of Sequoia but it looks very capable and seems slightly cheaper than its main rivals.
Although I will never have need of such programs they are very interesting to see them as they develope.