I have worked in BI most of my life and concur with your sentiments. I have a slightly different take on the whole commercial vs Open Source. I think organisations should embrace both and make them both first class citizens. In BI space I would say go with Tableau/Power BI/Cognos for all your day to day dashboards and reporting but don't try use Tableau to create printed reports (still requirement in some industries). Tableau wasn't designed to create print PDF reports. Go with an Open Source solution like Jasper Reports[0] or BIRT[1] to create the printed reports. The essence of what I am saying is companies should use Open Source to fill in gaps not covered by the commercial software. Commercial software is good for end users. Commercial companies provide manuals and training is available from partner organisations. This means a lot for none technical users.

[0]https://community.jaspersoft.com/ [1]https://www.eclipse.org/birt/