It's a constantly changing situation.
Clearly, each income stream contributes to production/distribution/ profit and publishers balance the two, or find an alternative non retail distribution network.
'Free Sheets' traditionally had a poor reputation for editorial quality or for turning circulation into actual Readership though the London titles have challenged those prejudices in recent years.
The 'Paid For' Titles will still argue that they deliver a more targeted and more qualified readership to advertisers than the 'Free Sheets' so it's an ongoing debate.