`cat /dev/random` may still block, but only once per reboot. It may block if it is called so early that not enough entropy has been gathered yet. Once there enough entropy has been gathered it will never block again.
I think this is a change for the best, in particular this bit sounds completely true to my ears:
> Theodore Y. Ts'o, who is the maintainer of the Linux random-number subsystem, appears to have changed his mind along the way about the need for a blocking pool. He said that removing that pool would effectively get rid of the idea that Linux has a true random-number generator (TRNG), which "is not insane; this is what the *BSD's have always done". He, too, is concerned that providing a TRNG mechanism will just serve as an attractant for application developers. He also thinks that it is not really possible to guarantee a TRNG in the kernel, given all of the different types of hardware supported by Linux. Even making the facility only available to root will not solve the problem: Application programmers would give instructions requiring that their application be installed as root to be more secure, "because that way you can get access the _really_ good random numbers".
The number of time I've had to deal with security-related software and scripts who insisted in sampling /dev/random and stalling for minutes at a time...
* Only FreeBSD symbolically links, and it does it in the other direction. urandom is the symbolic link to random.
* OpenBSD has four distinct character device files: random, arandom, srandom, and urandom.
* NetBSD (as of 2019) has two distinct character device files: random and urandom. They have different semantics from each other. https://netbsd.gw.com/cgi-bin/man-cgi?rnd+4+NetBSD-current
$ ls -l /dev/*random*
lrwxr-xr-x 1 root wheel 7 Dec 10 15:05 /dev/random@ -> urandom
crw-r--r-- 1 root wheel 45, 0 Jan 6 15:30 /dev/urandom $ ls -F /dev/*random*
/dev/arandom /dev/random /dev/srandom /dev/urandom
$Edit: better link