This.
I worked full time for 10 years before I started an MS in Data Science. The MS took me 5.5 years to finish with a full thesis while working full time.
Physics major in undergrad. When I first started working I learned Excel and Access first. Then I got into SQL Server. Then I learned programming in VBA and did a lot more complicated stuff with Excel and Access. At one point I was almost doing SQL Server DBA work but I got into doing analysis in Excel. Things like simple linear regressions and building complicated reports via pivot table. Did some more complicated things in SPSS like survey design and response. This was all before starting my MS.
My point is that before I started the MS I had substantial experience working with data and working with different software packages that did "stuff" with data. I knew SQL like the back of my hand, knew how to work with CSVs, BCP data, looping. Things that sound simple but if you're seeing them in an MS program for the first time can be really hard to get. The kids who washed out were the ones who had no experience working with data before and couldn't keep up.
I see that in my professional life now. I've worked with several PhD Data Scientists (mostly math PhDs) who couldn't do anything. They couldn't work with data, they didn't understand building data structures, they couldn't handle the ambiguity of most real projects. They expected to show up and have someone hand them a data set with all the variables nicely coded and a nice target made for them. In the real world it doesn't work like that. It's usually; here is a vague problem we're trying to solve and here is our entire data warehouse...go. Those guys didn't last long. They either couldn't or wouldn't learn the dirty parts of the job.
Anyway, I also agree with the poster who mentioned Data Science is just a trendy job title. I don't agree that your average DBA or software guy was doing that type of work. The guys doing Data Science stuff back in the day were just Data Analysts, Analysts, Statistical Analysts, etc.