Claiming that old JRPGs had random battles because of "weak hardware" is damaging to the gaming history and genre perception.
I find it damaging to the gaming history because it creates a false assumption, and not a clear view of what old games were, leading to underestimating old hardware and often overpraising certain games for pioneering stuff when some other games of same time or even older have made it.
Every JRPG with NPCs could've affort roaming encounters. Final Fantasy II did that with empire soldiers. Then SNES Romancing SaGa has roaming encounters.
As some people have already said, random encounters create the thrill of resource managing, as you have to think in advance which items to get. Thus creating dungeon crawler experience - as JRPGs evolved from those.
When the main selling point of JRPGs became a story, the gameplay turned secondary. So the gameplay designed for patient gamers who can enjoy dungeon crawlers, has to be redesigned for players who seek story first.
So please, don't say that random encounters are results of old "weak hardware" that stuck. It was always a genre convention that simply got unpopular once genre started to aim at mass consumers.
If someone puts their dedication to it, the OG NES Final Fantasy can be hacked into a game with roaming encounters. Many dungeons in the game have bats - so they do have roaming NPCs, so someone could program more dungeons to have roaming NPCs and make them trigger fight when they touch you, like making four tiles around them work as encounter tiles.
This will disprove the "weak hardware can't handle non-random encounters" myth.