The type of person who makes partner at Bain / BCG / McKinsey
or their botique equivalents can definitely have that kind of trajectory in a technology company.
I would contend that 5 year EV is probably higher in tech than across all of finance unless you manage to get into only the MOST exclusive megafunds (Hellman-Friedman, Silver Lake, Bain Cap, or Apollo, as most are coming in as associates in 200-300k range) or exclusive HFs (Viking, Citadel, Elliot) and even then, you're usually on a 2 year contract or up-or-out plans. The HFs will need to see you perform well to get anything more than base and your bonus (the chunk of how you get comped) will be at the discretion of your manager anyway.
I don't think it's reasonable to say we're in a bubble because of a $80M fund around developing for a new platform. Few companies truly become platforms, and it's a misnomer to call it a bubble if this only happens to one company. It takes a lot of money or momentum to develop one. Facebook had by far the most compelling one in the last ten years, and the obvious incentive there was it's >300M users at the time. The case is less compelling for a B2B platform like Slack, but it makes sense as many of these investors also invest in B2B startups that can gain huge visibility through the Slack platform.
By having six investors in the fund, each fund can mitigate risk of Slack's platform not getting traction while lowering the barrier for developers to enter. This slideshow by A16Z outlines why the venture capitalists (including some on the list of Slack fund contributors) are tightening their belts around investing and telling companies like Slack to generate reliable business models rather than IPO prematurely.
This premature IPO behavior was the reason for the last bubble, and I think this investment fund is proof that we are NOT in a bubble. The new strategy for these investment funds is to allow their startups to generate revenue on a much more stable basis without the need to go public (and get cash for equity) for this to happen. Most B2B companies would eventually benefit from a recurring-fees model built around the Slack platform, and this enables smaller, fledging companies to scale much more quickly towards long-term cashflow positivity.
In all, the kings of tech companies are those that find some sort of platform or natural monopoly. Slack may be next in line to follow Airbnb, Uber, Twitter, Facebook, and Google respectively. Overall, by allowing a method to build these platforms while not going public, investors increase returns for their companies in the short AND LONG term while maintaining a course of innovation!
A good comparison that hasn't been mentioned much in this thread is Salesforce's Salesforce1 Fund, which launched with $100M in 2014 to encourage people to build around the B2B app-creation platform it had launched a year earlier [0]. As the parent post mentions, it's important to make the case "compelling" for building best-in-class integrations with a relatively-recently-launched platform (whether or not that platform is sponsored by a historically huge corporation or not).
It's an interesting point that bringing multiple sources of external capital to bear on an ecosystem via a multi-sponsor fund, rather than into the business itself via an IPO, allows the business to grow at a natural rate, and avoids Slack contributing to a "bubble" in which companies race to go public to launch their own platforms. I think we've learned from the last time around that the public markets aren't the best place to manage expectations in technology.
As for why the sponsors made this investment, there's a very good case to be made that (a) efficient free-form communication within agile teams at small and large companies is a pattern as crucial to developing modern businesses as a CRM, and (b) Slack is perfectly poised to capture and hold this new market in the same way that Salesforce was. Certainly worth a $13mm commitment that's diversified amongst companies whose teams could still pivot should Slack not work out.
