Moreover, with lawnmowers, some weight is a good thing.

There are some things where people associate weight with quality(expensive watches, bar glasses, pens, etc). A low weight lawnmower may be associated with being cheap and flimsy. So having the battery weigh more is actually a good thing for the lawnmower. There's probably an optimal point where you want the lawnmower to weigh enough so it feels sturdy (and stays where you put it), but not so heavy that an average person finds it unwieldy.

In contrast, with a consumer electronic device where lighter is always better and any weight from the battery is a bad thing. So the manufacturer has to spend more money to try to get the battery to way less.

I think the spokesperson from Sony showed Mr. Ockenden a lot of patience in actually answering his question, rather than just calling him an idiot for comparing laptop and lawnmower batteries, which was fully within his rights to do.

I imagine there's also some lifespan and related warranty issues.

Laptops see a lot of use and the batteries are probably going through nearly continuous discharge/charge cycles. In contrast a lawnmower would be used maybe weekly or power tools that would be used intermittently. There's probably some relationship to the number of times the battery goes through a charging cycle and the additional cost. Note that even if both items have a 1 year warranty, the fact the laptop's battery goes through more frequent charge/discharge cycles and more frequent use, the risk of a failure requiring a replacement is higher likely resulting in some additional warranty costs that need to be considered.

I think the original author should have thought through his rant a bit more before he posted it.

Strictly speaking, SMS has more in common with voice than the regular data traffic (email, http, etc). SMS travels across the digital control channel within the broadcast messages for the voice channels. Within the core of the network, it's transported on the SS7 network, which is the control network used for voice. So it is segregated from regular data.

IMS-based instant messaging will adapt fine to a 4G network, but there has to be some sort of standardized SS7 and IP gateway mechanism for the IMS network. It's not hard, but it's easier for operators if there's a reference that the operators can use.