Support for multiple analog signal formats did not become common on TVs until people started moving away from CRTs and towards flat panel LCDs and plasmas. This transition lasted a pretty long time, as both LCD and plasma presented numerous drawbacks compared to CRTs (LCDs arguably still do), and CRTs were still very cost-effective even well into the '00s.

Adding support for signals used in other regions to an analog CRT display meant adding more circuitry, so this feature was largely relegated to very high end sets and professional video monitors.

With digital flat panels, those analog signals were now being captured with an analog-to-digital converter. How to translate the sequence of numbers representing a formerly analog signal into something usable by the panel could now be defined in software, or even very compact digital hardware. This makes it more cost-effective to just produce one version of the decoder that works in all regions.

True in theory but in practice it wasn't much of an issue.

Especially as late as when the DVD came.

And the purpose of it wasn't geo-restrictions either.

The impact might differ a lot depending on your region and where your interests are.

Living in the SECAM region and wanting to watch US/british stuff makes it a lot more prominent issue that if you're in the PAL or NTSC area for instance.