hey viktor,
good question and i guess hard to answer - especially, as i was in your situation at the beginning of the 90s.
i guess due to the fact that the whole "techno" industry was just emerging, the number of labels seemed a lot smaller and their reportoire a lot more focussed on a very specific style or genre (be it strictly rhythm or harthouse). that's why we decided back then, not to even try sending out demos, but doing it ourselves and starting our own little label. ie finding our own niche or "sharing our vision"...
the whole process of shopping and promoting your own music was a lot different then. arguably harder. but when we ran source rexords in the 90s, we were actually trying to catch up with the demos people were sending.
nowadays i am receiving so many demos - despite the fact that i don't even actively run a label at this point - even if i wanted to - i would never have the time to listen to all of them...
taling from my experience, people seem to be most successful, when handing me their self pressed first record. these i will always give a listen at some point and i love playing them because it is a good feeling playing tracks that no one else has heard yet. in some cases people have picked up on these when they appear in my mixes online...
however, there is no guarantee for anything and it could be a total waste of money, personally i think that self releasing still is very legit!