I am referring to businesses that have thousands of transactions per day, which works out to millions of transactions over time.
A transaction and also an address aren't very large, though.
One address: 160 bits = 20 Bytes => 1M addresses = 20MBytes = 20MB
One transaction: around 500 Bytes => 1M transactions = 500MB
Even a factor of 10 higher (that's a lot) due to implementation inefficiencies and whatnot would be 5GB of RAM
for a business.
People often have their Chrome process eating this amount of RAM on their normal personal laptops. I believe a business can afford buying 0.5 to 5GB more RAM.
I believe we've drifted off-topic quite a bit, though.
Okay, that is fair enough. Some businesses might go a factor of 10 higher, especially over time, and hit 50GB, but I don't think it would be especially unreasonable for a business to use that much RAM.
My original solution anyway was to use a new seed and keep the old backups, even if the above would get to be too much.