By limiting a dog's lifespan, you force dog-lovers to purchase a new dog after a few years.
Any company innovating a long-lived dog would saturate the market quickly and go out of business for lack of demand.
The only way around this is a support contract or a subscription model.
You could lease a dog for an annual fee. The benefit is obvious to anyone with a bit of business sense: After only a year or so your customers will have bonded with "their" dog and won't want to part with it anymore.
So you can offer the first year at a heavily discounted rate and then jack up the subscription price as much as you want, the market will bear it.

And if they fail to pay their rates, just send in Kristi Noem. She'll do what needs to be done.