[Brightcolours]

There's also no "classic" compact standard zoom lens for DSLRs. They used to offer a 28-80mm but the only thing that comes close to that is the 24-105mm f/3.5-5.6 IS STM and that's not really a small lens.

To be fair though - IMHO a $100 lens just doesn't make sense on a FF camera. This market segment doesn't need one. If you got financial constraints or like small gear, full format is just not the way to go.

Well the very popular Sony 28-70 ,Sony 28mmf2.0 and Sony FE50mmf1.8 are here  to prove the opposite
Check the popularity of Canon 40mmf2.8 in Canon full frame world
I would be very happy to get the upcoming Sigma 45mmf2.8 if it's a pancake even if I already have the 50f1.4
I am very happy now using Canon 28mmf2.8 on EOS RP, although I rarely use it at f2.8 and I own 24-105f4, on his 6D2 a friend of mine, sold his 24-105f4  and is using the good old Canon 28-105f3.5-4.5

That the Sony 28-70mm is "very popular", what is that based on?
Is the Sony 28mm f2 a "classic standard zoom lens"? Or a $100 lens for FF? No. Then why do you mention them? Same goes for that 50mm f1.8. Which is not a very popular lens, due to its faults.

It is fine for someone to use an old 28-105mm of course, but is that a very popular choice? And not for the pixel peepers, for sure (same goes for that funny little 37-70mm I found).