If the idea here is to introduce phones and televisions into established settings, that's a timeskip of several hundred years, which is probably not conducive to the storytelling for most planes (barring exceptions like Kamigawa being set very far in the past), and you already have quite a range of societal development to work with as you approach the steampunk aesthetic which is still accepted within the scope of fantasy.
I'm not really sure what you're getting at here. No one is suggesting that planes like Innistrad should have cell phones, only that it's ok if new settings can work with that space if it fits the world.
This is... incorrect. While it has a lot of aesthetics that line up to the rough period in our history where the industrial revolution happened, Innistrad very much doesn't have the needed precursors to kick off the industrial revolution (no coal mines, for one thing!). Heck, almost all of the things that look like advanced technology on Innistrad are unique craft-pieces by mad scientists or actually just weird applications of necromancy - if you only look at the replicable stuff, it's solidly early modern (and the social "technology" of the plane is very medieval).
To be fair, we don't see much of the resource extraction on Innistrad beyond
Woodcutting,
Corpse-Digging,
Blood-Sucking, and
Rooftop Storm. Just because we don't see the mine from which
Village Ironsmith is getting his material doesn't mean the production chain doesn't exist. It's not even like coal mines were a new thing by the early 1800s; people had been using coal for various purposes for several centuries at that point.
Beyond that, there are several more modern elements to the Plane that definitely could be utilized in the story. For example, electricity is already a commonly used resource on Innistrad. It has applications
both in and
outside of polite society on the plane. Unless this is simply some new innovation that has only recently appeared on the plane, you'd think someone would have come up with something like an incandescent lightbulb by now. Even then, half the people working with lightning are scientists in some capacity anyway– it's definitely plausible that someone could have come up with a game-changing technology between the first and third visits. Maybe they're a ways away from proper industrialization, but there's certainly room for something like a "mad science" set to exist.
But either way, I think this whole conversation misses the larger point. Innistrad has intentionally been written to keep the status quo fairly similar to that of the first Innistrad set. Shadows over Innistrad reversed the outcome of Avacyn Restored and actively removed Avacyn from the board for future stories. The end of Eldritch Moon locked Emrakul away for future use but minimized her influence for future stories, specifically to reset the plane to its 2011 state. The only major difference going into Midnight Hunt was adding in the
Hedge-Witches, who, despite apparently being an ancient force on the Plane, were only mentioned for the first time. The influence of Emrakul and the Eldrazi were absent from the set, the permanent loss of Avacyn was barely explored, and the resolution of the two-set story allowed for things to once again return to something similar to the first outing. This is not good storytelling– it keeps the world fairly stagnant, while closing natural opportunities for future growth. I think the Mad Scientists of the plane inventing something new would be a good way to move things forward without needing to continuously retcon the existing lore. The problem is, since Innistrad exists at the end of the acceptable timescale for older Magic worlds, having a set revolve around the mad scientists would likely lead to places that feel dissonant from normal, even if it is a natural extension of the setting. Worlds like New Kamigawa, Kaladesh, and Duskmorne help to expand the acceptable range of technological levels for Magic sets, and make it easier for something like a mad science Innistrad set to happen.