Hmmmm...... can't say I agree but I don't pay super-close attention to their market share.
Seems like E1 is in the process of introducing several new products. Typically when that happens, most of the marketing $$ goes towards the product launch. Course, that takes away from promotion of other products.
I've seen several E1 products on shelves lately; new A2Z, new Wash as U Dry, aluminum wash, the Wet product line is represented well.
It might also be that the competition is upping their marketing $$ to get primo shelf space and end caps. Also I've seen numerous floor standing merch displays for other brands which have got to cost beaucoup $$. Paying for shelf space is one thing - paying for floor space is another.
So, it's prolly several business factors at work. Personally, if I worked for the competition and knew E1 was introducing new products, I'd spend a ton of $$ to blunt the positive effects of the intros. Consumers are *heavily* influenced by advertising of car care products. Anything you can do to defelect attention to your brand and away from your competition is critical.
Of course, this is all speculation by me.
