electronic check in - a delightful experience

How simple air travel has become -  I can reserve and purchase my ticket online by using my credit card, then print my e-ticket receipt and - ideally - check in at the e-ticketing counters inside the airport (well, i still need to drop off my luggage somewhere else). Some weeks ago I traveled in the US and all there was were e-ticketing counters. So I use my passport or credit card to scan and access my flight and destination, confirm and then receive my boarding pass. Not so, because in this case my passport was not recognized. I had to ask a clearly stressed service person to help and all she did was exactly the same what I had tried before with the same result. I was then directed to a single counter with a long line of passengers waiting, obviously having faced the same problem. What's the point making a process simple at the start while anything else has not been worked out properly ?
If I need credit card and/or passport to book my ticket, check in and get through immigration, why can't I just use same to board a flight ? And what are e-ticket counters good for when they don't work and I still have to go to a real counter to drop off my luggage ? I find this an utterly useless invention doing nothing but complicate a simple process. And why can't immigration check my passport during a flight ? Where else would i go when I am 10.000 feet up in the air ? Upon arrival I pick up my luggage and get out.
My proposal : Drop off luggage outside the gate for which I get a receipt with my assigned seat, passport scan to enter the restricted area inside the gate (thus serving as immigration) and proof that i have boarded a flight and the reverse upon arrival. All I receive is a receipt for my luggage and having a check-in near the boarding gate will also assure me that my luggage will end up on the flight i am about to take and not elsewhere. Oh well....