Likely this won't be terribly faster, and I did see the company near us using a machine that was building curb cuts directly.
There are hardly any of these in the UK, for example, and kerbs are nearly always made of kerbstones that are sunk into the ground. They have their own problems with sinking when driven on, and I imagine frost heave in areas where the ground freezes seasonally. But it does mean that a dropped kerb installation is quite quick. Most dropped kerbs are simple tarmac ramps rather than concrete castings here.
Include a built channel for injecting hydraulic grout a few months later once the settlements happened to correct it out.