In any large engineering organization with a bunch of products each of which are large enough to need multiple teams, multiple bosses are inevitable. The issues and technology are just too complex for any single boss to manage everything. A typical agile team member might be accountable to a resource manager for HR type stuff, a Scrum Master for team tasks, a Product Owner for team priorities and requirements, and multiple component stewards for component technical integrity. The key is to align everyone to a common set of program goals and clearly delineate responsibilities between those various "bosses" to prevent conflicts and avoid excessive communication overhead.

A "no-matrix" structure might work in a small organization which has basically only a single product. In that case it's actually possible for a single competent boss to understand the customer, product, employees, and technology well enough to make good decisions.

As far as I know a matrix organization normally means a two dimensional one, with two bosses. You're totally right that all those functions exist and influence your work, but I don't think it is normal to call them bosses.

In most matrix organizations regardless of dimensionality each employee still has only one formal manager who deals with raises, career development, and disciplinary actions. The other "bosses" such as project managers aren't officially considered managers in that sense, although the employee may be accountable to them for certain things.

I agree they have one formal boss but I thought that in practise they had one other person they reported to for their day to day work and results.