Would different tyres make much of a difference?

[SkipdiverJohn]

I was horrified a couple of weeks ago to have my first flat tyre when riding on Marathon Originals ...... Clearly the air must be escaping back through the (Schrader) valve, so I pumped up again and quickly disconnected the pump... and it stayed inflated.
But I conclude that it's a failed valve and that riding pressure was making it leak even without a pump attached. I've thrown it away - which offends my hatred for waste, as I only like discarding a tube when there's no room between the patches for more patches.
But at least I know that my beloved Marathon Originals have still not had a puncture.

One trick I've tried for sticky Shrader valves is to give the valve a quick blast of WD40 then pump up the tyre immediately, followed by a further squirt after inflation. I'm sure that forcing air in also forces in some lube and helps prevent sticking.
The other trick I use is fitting old-fashioned metal valve caps in place of the plastic ones that come with tubes, as I believe they tend to seal better. I don't throw tubes (or tyres) away either unless they are absolutely knackered, and scrap tubes get used as chain sleeves or mounting bracket packing material.