In major law firms, the associates aspire to become partners in the firm, which is analogous to my interpretation when saying "equity".
I'm not sure it would work, but if it did, it could be a perfect solution for keeping a great team together for the long haul.
It's a consulting company not a product company; it may be significantly different when "making partner" at a product company. However, from what I've heard, each partner at Accenture essentially runs his or her own business within the larger scale of the organization. Success is directly tied to the success of the internal mini-businesses. It is, however, an example of a company where IT professionals can become equity stakeholders in a private firm.
I imagine a product company would need to make the partners in charge of one product each (or maybe a couple of partners on one product) in order to avoid the "Too many cooks in the kitchen" problem.
Accounting and law firms may be a better example, though even they aren't as entrepreneurial as you think. They have their own regulations and internal politics.
At Andersen, at one point, I heard the number was $10M/yr of revenue.
It would be harder to figure out how much revenue is generated by an individual contributor (even if they are a superb coder).
Also, partnership usually involves leadership decisions
Seems to be largely working within the specific space of Silicon Valley YCombinator-funded startups, but I'm not sure how well it scales. There's a pretty sharp filter for getting into YC, and for someone without access to PG's connections, the chance of hitting it big or getting acqhired may not be worth the risk they take.
I don't want an incentive scheme to help make you money. Pay me 20-25% of the revenue I generate for the company and give me a non-zero chance to be a stakeholder and I'll work my ass of for you.