Is it though? There is nothing you can solder onto it that will gain any meaningful access and go unnoticed. Tampering with the supply chain is a lot more difficult, easily detectable, and wouldn't scale. I can use 100% open source software, in an OS where it's signed and completely safe from interference - except the NSA of course, but they are not interested in your money.
For example, in MacOS it would be extremely hard to "sniff the display" as in this attack, unless you take obvious steps to authorize screen access.
For example, in MacOS it would be extremely hard to "sniff the display" as in this attack, unless you take obvious steps to authorize screen access.