Company valuation isn't based on the complexity of the product, it's based on potential/future earnings. Sure, valuations aren't an exact science, but the fact of the matter is the market has decided at the moment that Slack in its current state has more earning potential than SpaceX.
However, complexity of a product does (or at least should) inform risk of future competitors. The market for instant messaging systems is relatively low-cost to enter, has lots of serious players, and seems to be moving towards a subscription model, which is easier to disrupt.
Perhaps a free protocol will win sufficient mindshare to commoditise the market, though I'm not optimistic - most players' profitability rely on walled gardens.
Either way, the market is replete with its varied biases, unfounded optimism, and information asymmetry.
SpaceX is not available to purchase in an open market. Soon Slack may be. If they were both publicly listed, maybe their market caps would means something. Estimated private valuations, not so much info there.
And the market is of course irrational and wouldn’t be the first time.
I’ve got nothing against Slack, but they are just another Snapchat.
They provide a useful service, don’t get me wrong, but suffers from the same disease as many other software companies that grew via venture investment.
Slack does not have vendor lock-in [1], which implies significant cost and thus inability for most customers to switch to alternatives.
In case you didn't know, Oracle has lock-in over their customers because their platforms expose proprietary features not delivered by competitors, or because they have certifications demanded by law in certain industries.
The cost of switching from Slack to something else is insignificant and there's nothing that Slack can do to prevent competitors from emerging, short of burning cash to acquire them like they did with Hipchat.
Slack does not even target the market of Oracle, because big enterprises prefer and even require on-site solutions. I've worked with German companies threatening to fire employees if Skype or Slack were found on company owned computers.
Comparing Slack with Oracle is like comparing Snapchat with Microsoft Exchange.
