as already mentined, the volume of higher quality bikes being produced now compared with the early 90's is massive BUT i doubt the quality of workmanship, components & materials are the same on (for example) a new marin compared with an early 90's version of the same named bike.
likewise with brands like spesh...... many moons ago they were desireable to the masses, now, they are catering to the bottom end of the half decent market and ruining the reputation of their top end stuff.
the example in question is my brothers bike, he bought a new hardrock sport a couple of years ago and it works, but it just isn't as good as i would have expected a spesh to be. for example, whats wrong with going for a matching groupset? its got tektro, shimano, sram and their own branded bits on there, it just looks sloppy and unloved straight out of the box and that will never make it desireable as the memory for me of the low to mid ranges now is a random frame with their name on it, crap forks, honest but nothing special wheels and from what i can tell, the cheapest cobbled together components they could find that week.
back in the early / mid 90's most bikes you saw, even the lower range bikes, had something that set them apart from their rivals in each price band, today you are essentially picking the colour scheme you want as most of todays bikes are probably built in the same place anyway.