Anything in that post that caught your interest in particular? I'll make it happen.
Basically the idea is how much can we provide with 'only' a 2G link (afaik equivalent to 2 56k modems).
Nothing can ever top the fact you have a cable from a satellite to your house!
That must have been a pretty long cable!
I don't see why you think this would be the case. A friend of mine lives down in Gilroy, CA (south of the San Jose) in a veritable mansion. He and his wife have done very well for themselves. Because they chose land over some SF row house their only internet access is a spotty 4G connection that really acts like a spotty 2G connection much of the time. No ISP is willing to run a landline out where he lives and WISPs aren't much better than the 4G. He's definitely not the only monied person with shitty Internet access.
Lost 2G users don't necessarily have 2G (or equivalent) connections all the time. There's plenty of places or times where 4G gets congested and performs terribly even when the end users have high end devices and nominally good connections. A lost sale because someone couldn't complete a form because of poor coverage on the subway is a lost sale.
Mobile Internet should never be expected to be some fixed value for any user. Someone with a brand new iPhone on a network with great 5G coverage can still be standing behind a lamppost or something and get 2G levels of network performance. Since an overwhelming percentage of web traffic is from mobile it doesn't make sense to not degrade gracefully in poor network conditions or just minimize resource use.
This means 2G, slow 3G or satellite using customers are extremely common. No G too, if they're using your product out in the field. I myself lived 30 minutes drive from a mobile connection in 2021. A sheep literally ate my internet by chewing through the cable from the satellite to the house.
So those users definitely exist in my demographic. And very much in the demographic of my clients, as potential customers.
Still, it seems to be a hard sell to make things work with crap connections or offline. First off, frontend devs resist because you're taking away their favourite toys. (Very rational from their perspective - their next gig is probably in banking or retail or somewhere else with ubiquitous fast internet). Second off, those allocating budgets are very hesitant to spend money on any software dev out of the mainstream. From their perspective software is risky enough given its expense, let alone doing something that might require specialists. (This may be more of an Australian thing, they're not risk takers like Americans).
So yes, you're very right on a technical level. I'm with you, and would love to talk to others who see this. On a more practical level - it's hard to make the stars align, even if it will land you customers.