€339 for a tip top case gets you the bigger case others are recommending. With the modules represented in the above rack that are the same as what is in the mylarmelodies video, you could probably get all that for about 2k if not less if you are prepared to wait and buy second hand. Its around the 2.5k mark you mentioned in your original post if you want to buy new.
I get what the other commentators are saying as both the people in the YouTube clips have much larger systems they are using in their normal day to day. That being said I still stand my point that its possible to build a nice groove box in a small pallet case, the proof is in the videos. The music might not be to the taste of others but for a techno groove, a drum, clap, percussion noises, bass and chord was achieved in the mylar melodies videos and it sounded great. There was plenty of variety too.
I would buy bigger modules than these though if I had the additional space available to me. I think I might put together an equivalent rack in a slightly bigger build with modules I already have to see how much it would cost :)
You will enjoy Eurorack, I was all digital too but if you have 2.5k to play with, its great fun :) and if you don't like you can get most of your money back easily especially if you invest in modules that are made by the more famous brands.