You don't really print to PDF.
You click print and pretend that still means something.
You click 'Print', select 'Save as PDF', and behave as though something has been sent somewhere to be produced. But nothing is being printed. Nothing is being rendered onto paper. There is no physical transformation at all. It's just a document being reinterpreted through a metaphor the operating system has refused to retire.
It persists because the metaphor is comfortable. Everyone understands what 'printing' used to mean, so we reuse the word and quietly ignore the fact it no longer describes the thing being done. Software is very good at this. It rarely removes old ideas, it just wraps new behaviour around them and hopes the interface is convincing enough that nobody asks too many questions.
'Print to PDF' is one of the cleanest examples of this. A feature that behaves like a printer, is named like a printer, and lives inside a print dialog, even though it has nothing to do with printing. It is closer to 'render this document into a portable snapshot', but that does not fit neatly into a menu, so we keep the lie.
And once you notice it, you start seeing it everywhere.
The save icon is still a floppy disk. Most people have never used one, but the symbol persists because it once meant something everyone understood. USB drives still ask to be 'ejected' as though they might physically object to being removed without ceremony. Software still asks 'Are you sure?' for actions that are easily reversible, as if we have all collectively agreed to preserve a little anxiety from older systems.
None of these are mistakes in isolation. Each one made sense once. The problem is that software almost never revisits whether those meanings still hold. It accumulates decisions, then builds new decisions around them.
PDF itself is a good example of why this works at all. It was designed to preserve layout and meaning across systems, to make documents behave consistently regardless of where they are opened. In that sense it succeeds almost too well. It became a universal container for information, and then inherited every workaround that came with trying to make documents behave consistently across decades of changing software.
So 'Print to PDF' survives not because it is the best solution, but because it is the least disruptive one. It preserves the idea of printing just enough that nothing else has to change around it.
Software rarely evolves cleanly. It accretes. Old assumptions do not disappear, they get layered, abstracted, and quietly carried forward until they become invisible.
Until you click print.