I have a Summa cutter. It's an older model: D140 that I got close to 20 years ago. It's still working reasonably well after all these years and I've NEVER changed the cutting strip. However, I rarely (almost never) cut all the way through anything. I always kiss cut. So I would suspect that you're wearing out the cutting strips with the heavy volume of decals that you're cutting completely through. Probably the same is true with the blades. Cutting through the paper liner is tougher on the blade than cutting the vinyl.
I've been using Clean Cut Blades for the past 4-5 years without issue, so I don't think you're having an issue caused by not using Summa blades.
I don't know about the others here, but I would consider 30K decals in 7 days to be a high volume for a plotter to handle. If you do the math, you're cutting 9 DECALS PER MINUTE NON-STOP FOR 8 HOURS PER DAY.
I have an old school steel rule die cutting machine. For that kind of volume I would have a steel rule die made and cut the decals out on a die cutting machine.... or sub it out to a local die cutter. This assumes that you're making large quantities of identical decals. Just my opinion, but I don't think a roll fed plotter is the correct machine to be using to mass produce decals that are not just kiss cut.