The margins are…
Too small now for Ltd to make any real profits.
The VAT man has taken away the zero/flat rate schemes so there’s nothing to be had there any more.
I know of one agency that has now scrapped the brolly scheme rip-off and put their drivers back to PAYE (and there’s only one reason they’d do that).
I dissolved my Ltd company some years ago, one of my friends has wound his company up this year and another will be doing so next April.
If the OP would care to use the search function here, there are pages and pages of material relating to Ltd status.