It is virtually impossible to give an answer to such a simplistically phrased statement.
Did the o.p. mean - did folk song come from 'the people'? - If so, yes, they most certainly did.
It is obvious from the use of vernacular, the familiarity with detail, the descriptions, - etc, that bothie songs originated with the Aberdeenshire farm-workers, that the forbitters came from the experiences of sailors who sailed before the mast, that the songs of the cotton industry came from mill workers…… etc. The fact that the songs reflect the lives and experiences of the people who sang them as accurately as they do pretty well confirms this – for me anyway. The clincher is the fact that the folk repertoire is almost entirely anonymous and the product of many rather than single composers, therefore, if Bert Lloyd was right, too poor to be acknowleged.   
If further proof were necessary, run your finger down the lists of our source singers and note their occupations – Walter Pardon, carpenter from a farming background, Harry Cox, land labourer, Phil Tanner, mill worker and farm labourer, Margaret Barry, street singer, Jeannie Roberson, The Stewarts, Phoebe Smith, John Doherty, Duncan Williamson…… Travellers/tinsmiths/horse-dealers - small farmers, navvies, factory workers, building workers……... ie 'the people'
If our folk songs are not 'the people's songs' whose are they?
This assumes, of course, that we are talking about folk songs proper and not those which are passed off as such nowadays, which are completely different cans of worms!!
Jim Carroll