I am probably hitting a nerve there, but most of the time 300 MB are well enough for legal private uses.
Transfering 3-4GB? I don't have that amount of private data that I created myself. Everything with such a size I downloaded from somewhere and the other person can do that as well.

But even if so, there's no need to pollute a communications network with such a big amount of data. This is where the already named platforms come in. These are designed to handle data to be transfered and don't just offer file transfer as quick & dirty solutions. And they are more secure too. If you transfer files via p2p, then both sides can be the cause for interrupted data. If you do it with a storage in between, one can turn off his computer after the upload while the other downloads.

When I think of big internet file transfers, I think about file compression.
But this would go off topic quickly.

To me, though, it only makes sense to transfer big files if they are heavily and well compressed, as it saves data, user space when backup is needed and time, on slow networks. It is wrong to assume that everyone have fast internet and huge amounts of data to 'play with'. So physical media and good compression is always good.

Talking about this... I think we have some experienced people here on this forum that GOG could request help on how to create well compressed offline installers.
Just a thought, as, if you think about it, things are getting absurd now with triple A releases.

Just imagine downloading 120 GB (Baldur's Gate 3, for example) on slow internet, with limited data per month, and with anything less than 1 TB HD/SSD.

Therefore this brings us to how badly optimized in files sizes and internal compression games are nowadays... but I think I will be banned before I switch the topic a third time. haha

Yes yes, and 640kB of RAM ought to be enough for everyone.

When I e.g. turned a bunch of old family VHS videos to digital (DVD ISO) format, those alone took a couple dozen gigabytes. Or when a close relative of mine got a new laptop and he wanted to move all the Minecraft worlds he had created over the years, I recall those also took quite a hefty amount of space.

I usually use netcat for such tasks.

Use h265, that helps a lot.
We had our Super-8 videos been sampled by a professional studio, so I didn't create them myself :P Never had a tape cam.
My "most of the time" statement still stands, videos are the (or 'a') exception and these you don't transfer on a daily basis over Skype.

The home videos have so much sentimental value to me and several others that I wanted to keep them as "original" as possible. So no re-encoding after I successfully got them into digital format.

You can always use the 265 to begin with. I guess they are currently stored as mpeg2, right? The person you want to send them to is probably happy about a smaller file size :) But resampling might be a little bit too much work.

What would be the big difference between this and just taking offline installers and transferring them to a USB?

Not sure GOG will make a more optimized installer by having it on a USB.

glad physical stuff disappeared,but some still cant keep up with progress
protect the turtles!!!

I see.

I understand the need but it sounds like a relatively niche service that would necessitate a pretty large increase in the price.

Personally, I would like to see my games come on a series of punch cards that read the data into my computer.

Now that would be something :)

But if we want to use "newer" technology, we could transmit them on FM or AM radio waves and have a tape recorder ready to record them.

Were there any games actually distributed this way?

My understanding is that games weren't really distributed until cassette tapes became a practical method of software distribution.

Yes, there were games distributed this way; in fact much to IBM's ire, the two most popular games were a baseball simulator and chess.