However, Riviera is fairly new model that just launched back in 2021. Based on the fact that BM expanding the line to 3 different sizes and even the new diver version, looks like they are confident about the future of Riviera, and i assume it will stay quite long in the catalogue. If the sales are good enough for them, i think they will supply the straps in long run. If you really like the Riviera, i would say you could buy extra straps. I have handled the Riviera and found the rubber and leather are of good quality so it should last long.
Myself, the deal breaker for me is the lack of screw down crown and lack of minute marker on Riviera.