strenght of marijuana now and before

I hear everywhere that pot has evolved over last 20 yeast or so, from iconic plant to almost a new level species, much potent and stronger

On another hand i hear stories about Cali, Mexican of European straines that were kick ass, but have been lost ever since

When i am trying compare the stories it does not add up, so how is it. You can say that i am a new-schooler (even that i smoke weed for a longer half of my life) I dont know the "cannabis of the past". Is it really true that strain's of the past were much weaker? or maybe not everybody knew where to find the good strains.

come on oldschoolers.....straighten me up!!

now im not an oldschooler thats for sure...
but i think whats changed is the knowledge and growth expertise!
back long ago, all pot was shipped up from columbia and mexico, where fields and fields of pot were grown without much care, thousands of tonnes were shipped all over. that weed was filled with seeds because they couldnt be bothered (or perhaps didnt understant) that males needed to be removed to better potency and more THC.
its only recently in past 10 or 20 years that people started growing in our OWN country, and as time goes on growers learn more and more about nutrients and how the plant grows.
thats why todays pot (sensimilla or whatever the fuck, seedless) is so much better.
i read a biography about a smuggler called Allen Long, book is called Smokescreen i HIGHLY reccommend everyone on Rollitup read it, its a great read!

way i see it is we the potency or whatever we are after is predetermined by dna. we are finaly learning to unleash those better genetics now and also by breeding strains together has changed this to.
ive been smokin for a long time and ive seen a change, we also have a different climate these days and that does effect them in a big way...less co2 in our outside air makes for smaller plants..less o2 as well. and warming. on and on

Thats what i thought
so once again weed is being demonized to the public to make people think that it is different than in hippie ages,
I am surprised that not so long ago people didnt distinguish (or at least did not pay attention) to separation of male and female plants,
but also development of systems like hydro is going thorough it Renaissances as we speak.
I still believe that there have been isolated growers who knew these aspects, and these were "long lost and remembered strains"
Media is trying to create a "new beast" out of the plant
also chemical additives so common in metropolises give weed a dirty name
thanx guys for little info here
hay