You have been very fortunate.

You would have made the connecting flight had the first flight been on time so the connection time was sufficient. Delays happen all the time and can cause a misconnect with a 35 minute connection or a 90 minute one (clearly more likely with a shorter connection time).

If you do contact US regarding this, I suggest you leave all emotion and hyperbole out and instead stick to the facts. The facts are this - your first flight was delayed by a few minutes and that caused you to misconnect. Your complaint is with the delay on the first flight, not with the connection time. My guess is that if you travel regularly and fire airlines with which you misconnect that you will soon have no choices left for air travel.

All you can do going forward is plan better. Many folks here often make 35 minute connections. However, if I'm leaving a delay prone airport like ORD, NYC or BOS then I will pad my connection time a bit, especially for evening flights or when I'm connecting to the last flight of the day.