Honestly speaking as a 2019 16" MBP user: The only thing that would get me to upgrade would be discontinuation of support for Intel machines or *significant* performance increases. At the end of the day, I don't care about the architecture under the hood: I care about the apps I'm going to use and the performance the machine will deliver. As it stands, switching to ARM means some meaningful sacrifices in terms of software compatibility. Personally I'd prefer to let the platform mature a little bit before switching.
And, based on this first Apple Silicon Keynote, I'm actually feeling even more confident in my decision to upgrade last year to the 16" MBP: I have the latest and greatest Intel offering from Apple that should be supported for as long as they support Intel chips. I am happy to sit tight while they work out the kinks in the new platform architecture for a few generations.
If you haven't already upgraded and do you wait or do you buy the current (year old) Intel offerings? I don't know - it's a complicated decision that I'm glad I don't have to deal with