The limitation of outboard stand alone DACs to decode SACD is based only on the fact that Sony refused to license products that output DSD from the transport. I think that in recent months or years, there is a crack in that restriction so that now some transports can output DSD or DSD converted to another decoding stream (PWM?), so that some DACs can now handle SACD.
Anyway, the hi-rez audio available via download and then fed to a DAC with hi-rez capability will challenge the fidelity of SACD, somewhat diluting Sony's attempt at monopoly. I think Sony's reluctance to encourage the spread of SACD technology to other companies was a marketing disaster for them and backfired, like Betamax, another superior technology that died because Sony was greedy.
Anyway, the hi-rez audio available via download and then fed to a DAC with hi-rez capability will challenge the fidelity of SACD, somewhat diluting Sony's attempt at monopoly. I think Sony's reluctance to encourage the spread of SACD technology to other companies was a marketing disaster for them and backfired, like Betamax, another superior technology that died because Sony was greedy.