You're probably right, but many/most seem to view them like Stonehenge in that if we never had them we wouldn't build them, but there's no point in removing them now.I also don't think the arguments are weak. To me, the entire concept of monarchy in a modern forward looking nation is perverse. An institution that only belongs in fairy tales.
As said above, remove the monarchy and you'll only get some other twat who fancies being top man or woman, and being rewarded for their political failure.
Someone like Johnson, Starmer, Junior Kinnock, Mandelson, Emily Thornberry, Saddiq Khan, the list goes on.
Your argument is dogmatic, tenuous and nebulous, at least mine is cynical enough to recognise how events would sadly play out in a new UK republic.
It's all rhetorical anyway as there's no general appetite for their removal as Head of State.
Your mention of France is interesting too; clearly you've missed Macron's failures and general unpopularity, along with most of his forgettable forerunners.