Oh, I can't prove anything, but to explain what I mean a little better, renting the first is a much more natural progression. Like a hermit crab moving up in shell sizes. You rent the first property as a consequence of buying a new house, rather than as the entire purpose of the second purchase.
I think we would be better off with more businesses and less private landlords in the UK. The current situation doesn't work very well for many tenants.
How do you define "business"? BtL landlords with a property portfolio are businesses.
Excluding those there are very few businesses that rent homes. The few that exist work at the lower end renting social housing.
There have been severe criticisms of business-landlords. I'm trying to find some cites but business landlords have been implicated in poor maintainence, leading to deaths from carbon monoxide.
Letting agents don't own the properties, they just handle the details for the landlords.
Not all but many private landlords can be fickle, turfing you out on a whim, getting into the business without realising the costs, basically having an amateur attitude to the endeavour.