The 2015 that Old Biff returns to is a timeline in which Marty was sent overseas to boarding school and Doc Brown was put in an asylum (and likely didn't even invent the time-machine...causing a paradox).

Ah, but you do notice in the movies a certain lag between the causal event and the subsequent change. I don't remember how soon after (old) Biff got back to his present that Doc and Marty left, but could it be seen that the "chronal" changes didn't catch up to the future by the time they had left for the past (85)?

takes out flippy cell phone and wishes it made a little chirpy sound when he flipped it open

I would be very surprised if there weren't a way to make your cell phone make the little chirpy noise.

I think X used to be 20 years, ita. The '70s were all about the '50s revival, for instance.

On the other hand, Star Trek: TOS, with its cheesy sets that never looked convincing, and its velour outfits with bellbottoms, manages to get a number of things right, not the least of which being small devices with flipping lids that you can use to speak to someone who is very far away from you....

Also, they had tiny little plastic disks they put in their computers that looked a hell of a lot like 3.5 inch floppies.

Ah, but you do notice in the movies a certain lag between the causal event and the subsequent change. I don't remember how soon after (old) Biff got back to his present that Doc and Marty left, but could it be seen that the "chronal" changes didn't catch up to the future by the time they had left for the past (85)?

Yeah, you could say that. Though Doc at one point explicitly says that the temporal change around...whatever Marty's girlfriend's name is..."instantaneous".

The 90s will be that bad too, in a second or so.

Yeah, man. Remember those trapeze shirt/dress things?

Although, I watched Reality Bites the other day. Most of that still looked ok to me.

Ah, but you do notice in the movies a certain lag between the causal event and the subsequent change. I don't remember how soon after (old) Biff got back to his present that Doc and Marty left, but could it be seen that the "chronal" changes didn't catch up to the future by the time they had left for the past (85)?

Yeah. Have any of you played The Journeyman Project ? In that game, alterations in time move along the timeline chronologically, altering as they go. So what they did is keep a disc of recorded history way back in the time of dinosaurs, so that it wouldn't be affected by people wreaking havoc across time. It probably doesn't make any sense, but it's a cool idea. It and its sequel are kickass computer games.

On the other hand, Star Trek: TOS, with its cheesy sets that never looked convincing, and its velour outfits with bellbottoms, manages to get a number of things right, not the least of which being small devices with flipping lids that you can use to speak to someone who is very far away from you....

But look at some of their food, those little cubes and polyhedrons are magnetic. Magnetic food!

Though Doc at one point explicitly says that the temporal change around...

Yeah, take HIS word for it.

Also, they had tiny little plastic disks they put in their computers that looked a hell of a lot like 3.5 inch floppies.

Also, they were one of the few shows of their time to feature computers of the future that didn't use punch cards. Not to mention a talking computer that responds to voice input.

I still maintain that fashion will never be as bad as it was in the 70s—when laughably bad perms, gold chains, polyester in day-glo colors, bell bottoms, and platform shoes all combined into a staggeringly awful whole. Gee thanks, Professor Leary!

The 90s will be that bad too, in a second or so.

I'm still waiting for super baggy pants to go the way of the bell bottom. Granted, bell bottoms came back, but that was just 70's nostalgia.

I think the stuff from the 90's that will look bad will be less the original-to-the-90's clothing styles, and more the trend towards OTT tats and piercings.