This is not at all true. The Power Pivot add-in provides a mature in-memory columnstore database engine with no hard row limits - this can easily manage 10s of millions of rows, and with a decent model architecture can grow to 100s of millions. When upgrading to SSAS Tabular on a server with enough RAM, billions of rows are not unreasonable.

Additionally, the hosted solution allows Excel Services to be the presentation layer, but the real push is toward Power View.

I would suggest you do more research before spreading this disinformation. There has been significant development on this front and what you are saying is very much out of date.

What I wrote is true for MS BI on Sharepoint 2013 with MS SQL Cluster 2012 in real world. It's probably the co consultants fault to use SQL2012 instead of SQL2014. MS mentions the new 2016 release on the upcoming MS SQL version will do away some of the current limitations, as you mentioned.

SharePoint 2010 and SQL Server 2008R2 introduced support for hosted Power Pivot workbooks.[0]

Power Pivot is the Excel add-in (available for Excel 2010+) which enables dimensional modelling and >1M row analysis in Excel, and which can be transitioned to a hosted environment via SharePoint and SQL Server.

Starting with SQL Server 2012, SSAS includes Tabular mode, which allows a seamless upgrade path from an Excel Power Pivot model to an SSAS instance.

This is seamless because the same DB engine is used in both products. Power Pivot runs a private, anonymous instance of SSAS Tabular behind the Excel process, with a few features disabled (e.g. row-level security).

Power View is a high level visualization and dashboarding tool introduced for SharePoint 2010 and 2013 as a part of the SQL Server 2012 SSRS module.[1] This is the visualization tool designed to pair with Power Pivot and the Tabular model. It is also available as an add-in for Excel 2013+[2], and as part of the standalone Power BI Desktop[3] which has been available since Power BI portal's general availability in July of 2015.

I do not know what you are referring to by saying that there is a 1M row limit in practice with SP 2013 and SQL Server 2012, because this is simply not the case. If your organization is not using the features and these are pain points for you, I'd love to have further discussion with you offline - my email is gregory.baldini at gmail dot com.

[0]https://technet.microsoft.com/en-us/library/ee210682(v=sql.1...

[1]https://support.office.com/en-us/article/Power-View-in-Share...

[2]https://support.office.com/en-us/article/Power-View-Explore-...

[3]https://powerbi.microsoft.com/en-us/desktop