There seem to be some disagreement on your post. One could argue for a slight bit of moderation, but your overall point is unquestionably correct. Fluence, BYD, Samsung SDI, LG Chem and traditional names such as GE, Parker Hannifin, Siemens and AES are larger than is Tesla in stationary energy storage. There is indeed massive opportunity for Tesla too, not least because of Autobidder.
We must all be honest enough to realize that when giants such as GE become the producers for the world's largest wind turbines, however briefly they hold that position, they recognize that those turbines will count for little without massive storage to support it, and extremely adaptable grid services to support them both.
Tesla accomplished great things with Hornsdale and they['ve begun to do more. They are famously 'battery short' so TE products have Samsung SDI, LG and other suppliers for the cells. As Tesla states, vehicles come first. That opens the field more for all those utility industry traditional suppliers.
Two years ago I was convinced that Tesla has a huge competitive advantage for stationary storage. They still do, because the world is constrained. Neither utilities or homeowners will be thrilled to wait two years or so when fast deployment is one huge potential advantage for batteries. That means Tesla will probably be a major player for powering new residential developments, for which solar roof is a really major advantage, as is Powerwall. That does not make Tesla a major utility player.
Nothing in this suggests that TE cannot be a major business. However, Tesla support is inadequate even in the primary auto business. Powerwall support seems to be fairly similar.
Tesla now have two huge challenges in customer service. Every single thing in Vehicles including sales, delivery, parts and service. The vehicles themselves are quite wonderful. The second one is in Tesla Energy. In that one excellent customer service is a standard expectation and Tesla does not provide that.
Sadly, this is such an impediment that I believe the Tesla growth constraint is now customer service, possibly even more than batteries and factory capacity.