What’s the reasoning behind the trend with motherboard manufacturers to make certain headers face sideways? For better airflow? For aesthetics?
This orientation makes it necessary for the front port plugs to protrude beyond the board edge. USB 3 header plugs in particular need at least 6cm of clearance to avoid having to bend the cable at a sharp angle. This requires an internal front-to-back depth of more than 30cm minimum inside the cabinet. Most inexpensive (up to 3.5k) cabinets available online just don’t have that kind of internal space.
And then there’s the matter of personal preference regarding convenience (I like the “front” ports to be at the front, not at the top), visual appeal and overall size. This narrows the available options even further. I build new computers from time to time for myself and for others and have been having a lot of trouble lately simply because of the need to choose a cabinet with enough clearance for the internal plugs.