Mostly, because we are too small for what we do:
https://www.odoo.com/page/all-appsOur promise is to cover all enterprise needs in a single software, while being super easy to use. It's something nobody succeeded for now on. On the market, you have two types of players: ERP (SAP, Oracle, MS. Dynamics) who deliver a huge business benefit but a poor usability (expensive and inefficient) and one-app vendors (trello, slack, mailchimp) who have a great usability but a low business value. The first category has a huge revenue per customer, and the second category can attract a lot of customers.
We think we can crack that, and offer the best of the two worlds: all business needs, fully integrated, with a top notch usability. We are in a very good position to do it, and be the first to do it. [1] (and every competitors try to do that but they are far from succeeding)
To succeed, we need serious investments in the product and the service offer. We don't need to be very big (e.g. 10.000 people), but 300 is too small for what we do.
tl;dr we want to fix a huge problem and to do it, we need resources.
[1] https://odoocdn.com/openerp_website/static/src/img/2016/home...