Erm … no … having both rented and bought properties myself …

The mortgage repayments are always lower than the rent on the equivalent property, so Alice and Ben save money compared to Anna and Bob ¹, because their rent not only covers the landlord’s mortgage but also a percentage of any shortfall s/he fears s/he might make during periods when there is no-one renting the property, plus of a pot of money for unexpected eventualities such as structural repairs. Additionally, if the landlord intends to make an income from the endeavour even more will be added onto the rent.

I have never been able to rent a property for less than twice the mortgage repayments — never … anywhere.

Furthermore, under normal-to-optimal market conditions, Alice and Ben will be in possession of a property that is increasing in value whilst they live in it, so, even if they have to sell it before the mortgage is paid, they will likely walk out of any such sale with a profit that Anna and Bob will not only never see, but might even find themselves obliged to pay more for, as the landlord deems the increase in worth of the property to merit a higher rental charge.

Finally, during the period described, Alice and Ben may make whatever changes they like to the property that fall within whatever planning regulations allow them. Anna and Bob, on the other hand, will almost certainly spend their lives living in accommodation in which they are not even allowed to affix Blu-Tac or Sellotape to the walls, let alone use nails, repaint or make structural changes. Moreover, they can be required to leave at any time simply by virtue of the landlord declining to renew the lease or even giving notice before the lease is up. It will be where they live but never their home — and the psychoemotional aspect of that alone is not insignificant.

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¹ Please use more obviously differentiated names in future; the two A&B combos are unnecessarily confusing