The Arduino also has about a 500-1000 times less RAM than most people's computers.
I think you missed by a factor of 1000 or so. 1k-2k byte (~1e3) on an Arduino, 1 to 4 GB on a typical desktop computer (1e9) That's a million times more RAM.
Mind boggling, if you were around when 64K was "a lot" of memory. But not so much as disk space. At my previous job, we had put together a "BIG" fileserver (the "labrea" tar-pit) that had a whopping 4GB of disk space. Most of the 100-concurrent-user mainframes of that era (about 25 years ago, now) had maybe 1 to 2GB of disk.