UPDATE. Another bad battery this spring. Sold it yesterday. No more electric riding mower for me. The electric push mower still works fine.
Even with the walk behind smaller battery powered mowers, they are a major sacrifice for most people causing them to severely modify their long-term mowing behavior.
There is simply no way the current batteries on the market will last as long as a gasoline engine will last.
I'll keep in maintenance is a rather moot point because it is not consistent among owners.
I have serviced slightly over 10,000 of these machines in the past few years since I opened my high volume commercial shop.
I get ones that have never had a starting or running issue at all and I get a lot that won't start every season.
I get mowers that come in every single year for an annual service and I also get mowers that never come in until there is an issue or a problem whether it be running or operation or a wheel is trying to fall off etc.
I occasionally get mowers better 3 or 4 years old that are working just fine but they figured it's about time they had something done to it or sharpen the blade at least.
So there is no guarantee that a person who buys a gasoline-powered mower is going to put more money into it for maintenance etc that would come anywhere near close to the price of buying a new battery in four to six years when you're likely to need a new one.
There are people who have kept their gasoline powered mowers well over 25 years and still mowing with them.
You can be absolutely guaranteed that he will need battery replacement in a shorter time than this.
Then of course you have the whole other aspect that has nothing to do with longevity but rather the fact that every battery power mower I have seen on the market that is a walk behind self-propelled or push style is underpowered and it will not cut either my front or back yard on one single battery charge.
People who claim they're not underpowered are probably those who take very good care of their grass and manicure it nicely and cut it when it's supposed to be mowed, only taking off the proper amount each month.
Many of us have no time or patience for that!
Many mowers are used almost like a brush hog and these gasoline powered mowers do a great job at it.