The original PlayStation didn’t come with an RF modulator. Neither did the Xbox or the N64.

The Super Nintendo was the last console I remember having one. The Genesis must have too.

But by 95 (PS in US) there were no longer the default. They may have still been available, I don’t know. Kind of doubt it but maybe I just didn’t notice.

I think it depends on market, at least some European / PAL PlayStations did come with an RF modulator[1]. The Dreamcast also did (UK at least), but that was an outlier, other consoles of that generation had RCA composite cables and an RCA to SCART adaptor.

You (nearly) always had to buy the RGB SCART cable you actually wanted for a good picture separately.

[1] random eBay listing, with RFU Adaptor pictured / listed in contents: https://www.ebay.co.uk/itm/364907339156 (Note Europe uses Belling-Lee connectors for TV antennas, so the connector is probably different to North American style RF boxes).

I don't know about other regions, but in the US console-specific RF adapters were available separately up to the Dreamcast/PS2/GameCube/Xbox generation, i.e. until HD over HDMI became the prevailing standard (Wii notwithstanding).

For the RF switch part, Nintendo actually recycled the NES design for all of them. It's kind of funny seeing that chunky gray box next to a GameCube logo.

I definitely bought an RF adapter for the N64 to be able to plug it into my old crusty TV at the time. But indeed, it was something you deliberately had to buy at that point and composite inputs were the norm.