Yes will add that, even in 1984, double layer boards were cheap, but, because they have to be made, at least at that time, with FR4 woven laminates, you see that even now you have a lot of SRBP board, single sided. Have seen a board in a copier, that had 244 jumper wire links on it, just to avoid going to double sided, because the board, around the size of your hand, had 20 connectors on it, and a single row of resistors, a few diodes, and a single electrolytic capacitor on it, but having an auto insertion machine put in 244 links, in 4 sizes, was still cheaper than making it out of FR4 and double sided.
Currently look at any remote control, thin SRBP board, which is not drilled, but actually punched to shape, and also the holes are punched as well. Then a green silkscreen layer, followed by a carbon layer for the links, and another silkscreen over that. Done to minimise cost to the max.
As to supercapacitors, those were common, cheaper than rechargeable batteries, and also used as no discharge in shipping, as they only got charged when the consumer plugged it in, so no sahipping risk due to having stored power in a battery, which is still a thing you need to declare in shipping. Flat capacitor is not an extra risk, but a pack of AAA cells in a remote means a higher insurance rate.