But both RSA and UBI need dirigisme. UBI is definitely a form of central planning, with a very wide reach, to shape the society, the people.
So UBI will never come with less dirigisme, but with more of it.
Disabled people will need more help than a fit 22yo guy for instance. Social benefits are individualized: UBI can't be the same for everyone and erase existing social benefits.
Also, governments HATE destroying public jobs ;-)
UBI probably for some extended time into the future would require some other social benefits, but to say that it requires "all" other social benefits is simply wrong. It wouldn't take a very high level of UBI to completely displace the need for existing General Assistance programs in the US, it would take a higher level to replace SNAP and TANF.