This is both only true for small transfers (not bulk/asynchronous transfers) and for the ~99th percentile. Large transfers have some buffer management and handshaking, so they tend to have highly variable latency that has a very fat tail.

The latency degradation for large transfers is so noticeable that most audio DACs (not just ones for gullible audiophiles, also for the pro market) use custom drivers and USB protocols. For 1/1000000th the data rate that a capture card would need.

but is it /consistent/?