I bought a house two months ago and have about a quater of an acre of mowable grass. I bought an 80v Greenworks Pro push mower for the job and can litteraly mow the whole lawn in one of the two batteries I have. The biggest thing for battery push mowers is that not only is it less finicky and quieter..but the VIBRATION. My hands thank me compared to gas. I really think that for push mowers (riding is a little different) short of the bottom of the market, there is no reason to buy a gas push mower anymore. That market is dead.

When it comes time to replace the batteries for your electric mower, you might consider getting an oldschool "reel" mower (the sort with no motor.) You might have to mow more often since they work better with shorter grass, but for a quarter of an acre they're pretty reasonable. The big advantage over an electric motor is lower operating costs in the long term. Of course it depends on what kind of grass you have.

You mow one large yard every couple weeks. Landscapers mow multiple in a day. It's already a low paying gig, with how expensive batteries are I don't think they'll be using electric equipment anytime soon.

I've heard of landscapers moving to Ford Lightnings and charging equipment on-site (and maybe while driving?). Of course, those are roughly $100k each so those are probably landscapers with much higher margins than your typical residential landscaper.