From what I can see just the opposite is happening. I know several Roadster owners who bought their cars with full intention to sell or trade it when the MS was available who have since changed their minds. Some of us simply fell in love with the Roadster and can't imagine selling it even though it was originally purchased to bridge the gap to a different EV.
I am in this same boat, I do not think I will ever part ways with my Roadster. The sad reality is that many people probably kept their Roadster because they got low balled by Tesla when they went to trade it in or due to poor private party resale value. For those of us who bought new- I am not sure if it makes sense to take a 60k+ loss after two years. I prefer the Roadster for daily driving as it has just enough space for my daily needs. The Model S usually sits in my garage as it feels far too big for daily use. Hopefully Tesla makes good on the rumors and we start to see some essential warranty and maintenance packages available. Liquid cooling, nitrogen cooling, CF body panels, BBK will be good surprises but I cannot see many people updating the old roadster- when the new one is only a few years away.