I get the attraction of OSFP, but in early days backward compatibility usually trumps future potential. If I'm buying an high density switch/router tomorrow (figuratively speaking), I'd greatly prefer the flexibility to use the density it provides for some existing lower speed connections. As long as QSFP-DD 'works', as a customer I'm not really concerned with which technology is more elegant or technically 'better'.

The problem this presents for OSFP going forward is that it encourages early adoption to steer toward QSFP-DD, which will tend to drive follow-on purchase decisions as well.