I jumped from a c64 to a PC because the apps I needed to run in college were on the PC.
From what I remember amiga's were never really advertised much. When I was growing up all the local stores had atari 800's and c64 on display. I remember seeing the cool 64 portable at the cheap KMart outlet and wondered what the heck people will do with that tiny screen. Commodore did some advertising, but their machines were on display so you could check them out.
The amiga was sold in maybe a few high end computer stores around here, you know the type that overcharged for everything and only rich people or buisinesses purchased from them. These stores sold the big box amiga's, I never even seen a real live a500 or a1200 untill I purchased one from ebay.
I new quite a few people with a c64 and we all traded games. If you have 2 or more friends with a specific type of computer and they had free games you could copy well thats the computer you ended up getting (well except for my parents who were cheap and got me a Timex 2068). I dont call that peer pressure, just being smart with your money. All of these people with the c64's went straight to the PC because of the pirate scene, or their parents had one at home for work reasons (well one guy went to the C128 for a few years but went PC after that).
Since the amiga's were sold in places you generally didnt go into, nobody I knew had one, no advertising at all,and they were expensive nobody knew about them or cared. Yes pc's were expensive at the time I got mine, but I ended up getting an $1800 NIB 286 for $600 cash because a friend helped one fall of the back of a truck if you know what I mean. Otherwise the $1800 price would have meant I would be using the crappy computers in the university labs instead of owning one myself ( I sold the c64 for over $200 with addons that subsidized my PC).
I always found that any PC that caught on in europe (especially britain) never did that well here. The brits loved their sinclairs while in the US their apeal dropped like a rock after the atari 800/c64 came out. same with the atari ST and Amiga. Also europeans used tape drives way after people in the US went to floppy only software. I had a fwe games on my c64 that were on tape and boy did they take a while to load.
Even now that I have a 500/1200 to play with I dont think I would have purchased one back in their glory because they didnt run the software that forced me to buy a PC in the first place. I think the amiga systems played games much nicer looking then the pc of their time (up to the early 90's), which is the reason I have them now. The PC saved me alot of agrivation during college, and being able to play some simple games (not like I had time going to school and working full time) was an added bonus. PC games didnt become extremely popular game machines like they are today untill the 386/486 came out in force.
The NES was popular because it played games other then the tired old space invaders variety of the old atari consoles and it was cheap. Parents with a few bucks always gave their kids something electronic to play with to either keep them from spilling cool-aide on their $3000 PC or just to keep them occupied for a few hours so their parents could chill out after a hards day work. Remember if your options are an old nintendo or that tired old atari 2600/5200 what are you going to play with?