Physical goods in a typical household Estimating how much of physical goods a somehow typical person or household owns today (say in the Western world, compared to former times) is not so easy I guess, but there is one single number that might tell it: the typical weight/volume per person that is transported when moving a house. (This gives not the number, kind and economic value of physical goods, but only their cumulated weight/volume, but that would be OK for me for the moment.) 

Removal companies know these numbers, and I wonder if they are available somewhere,  broken down by country, state or other region of the world, and of course broken down by time. (Of course the numbers from removal companies tell only about people who can afford to hire a removal company, but that would be OK for me for the moment, too.)

I would find it astonishing if these numbers had not grown significantly in the last decades, but I'm open to any answer. (For example, modern people might decide to dispose many of their physical goods before moving, and re-buy them at their new location. This would be interesting in its own right.)

If the approach via removal companies is not found sensible: Which statistics could you recommend alternatively? What about homeowner's insurances? Or are there official detailed statistics available, say for the U.S., Europe or e.g. Germany?

(If this forum is not the right one to ask such questions: Which one would you recommend?)
Those are some good starting points but I would refrain from using them as the end result. There are some fatal logical jumps in your example.

Moving house: A good one to use. If I were to guess, I think the ratio should have decreased due to tech. For example, we don't have those huge t.v. nowadays. No desktops for the most part. However, be careful about how wealth plays a role. Also, people moving into cities of California would be very different than of Colorado.

I think a better indicator would be the consumption category of GDP. Especially durable goods. You can find detailed numbers by year, state, category on the official website.

I hope that helps.

References:
https://www.bea.gov/data/by-place-us
https://de.wikipedia.org/wiki/Bruttoinlandsprodukt