That's a great question. In my first grows in the early 70's, to be perfectly honest, I was happy to get anything to grow and yes if it grew and when to Seed, I was thrilled. They were the days of potting soil, dirt from the outside, miracle grow fertilizer, and what light they could get from the sun.
So now we grow inside with a maintained environment of light, heat , humidity, and nutrients; we also know now, how much light. heat, humidity, and nut's we must give to get the plants to develop big seedless buds, add to that the the strains have been developed over the years to increase hardiness, and yields.
My opinion, gets answered with another question: So if we took today's seeds and grew them like we did in the 70's, most likely outdoors, potting soil, miracle grow, natural sunlight and buds going to seed, I believe that some (like in the old days) might make it but what would the quality be like?