I don't see how a property owner could be sued under PL for lack of a phone line (esp if tenants knew this).
However, were a property owner to refuse a tenants request to install a phone line on the basis that it would mean cutting holes in the wall, etc, that is another issue.
If a house has been leased w/o a phone line and the tenants knew this when they signed the lease, then I would argue that the legal obligation is not on the landlord to pay for the installation.
Morally, however, it would probably be more equitable to split the cost.
I think that it all comes down to demand and supply and the relative bargaining power of each party.
It is also worth noting that in some backwards parts of Australia, such as Canberra, where the infrastructure is ***** and the service not much better, phone connections can take weeks.
And btw. I am speaking from experience (twice).
MB