I guess you all are still missing my point. If Navi scales really well, then AMD had no reason to just release the 5700 and 5700xt over a year ago. In development, the engineers should know how well their design scales. Since 5700 was such as small chip, and if scaling was not an issue, then just making a bigger chip would not be that much effort. Why would you limit yourself to 2070 level performance? Do you not want to be known as a high performance company and sell chips? Why wait 1.5 years to make money when you can make money now? Things change, like the competition releasing a $700 card that is faster than the current $1200 card. You never sandbag yourself.
I'm a software developer, so I can only explain from that point of view. I have an app that process multiple requests, and things seems to work really well when the number of concurrent request is under 10. Performance wise, it seems to scale really well. But as soon as I am in a scenario where there are 11 concurrent requests, I start seeing issues. I start seeing locking timeouts, data being overwritten by parallel process, memory heap issues, performance issues. So, my program is only scalable upto a certain point. It's a leap to assume big Navi scales the same way as 5500 to 5700.
If Big Navi does end up performing better than the 3080, it's because the engineers had to do a lot of awesome work to get around the problems of RDNA1, just like how I would have to redesign my program to be able to scale above 10.