Services such as EOS Name Service offer the ability to buy custom name within namespaces they own. Since EOS Name Service owns the *.com namespace, they can delegate example.com to me. Can I then create x.example.com or does EOS Name Service still own that name?
Just a pedantic point first: .com is owned by the Block Producer StartEOS and they offer access to their custom name auctions for .com, .io and .eos through ENS.
StartEOS's account is the only one can create names ending in .com If you purchase example.com, you will not be able to create x.example.com. That right belongs to their account still.
Here's the relevant code if you're interested: https://github.com/EOSIO/eosio.contracts/blob/c046863a65d7e98424312ee8009f0acb493e6231/contracts/eosio.system/src/eosio.system.cpp#L394-L404