There are many common formats which are copied by various manufacturers that provide continuity of supply.

For example the PowerTip PC1602F layout (16 character x 2 Line) is followed by at least half a dozen different manufacturers. This is one of my favourite formats available pretty much all over the world, so if your 1st choice supplier suddenly has a problem, you can still get stock from alternative sources.

It's always a good idea to chose your components from an established manufacturer (like PowerTip) in the knowledge that the smaller ones will almost certainly make their own copies of popular parts at far lower prices than the original.

The alternative is to buy in bulk now and stockpile two or three years requirements... you then realise how expensive buying in small quantities actually is when you find 16x2 LCD's with Backlights at sub-$5. It makes you resent looking in catalogs like Digi-Key or Mouser when you know that they still have 100% mark-up even when you look at their 1000-off column...