Your argument is the same one as "nuclear submarines are impossible to build because I just thought about it for five minutes and can't build one". But Electric Boat Corporation from Groton, Connecticut delivers them regularly, on time and under budget (!). Googling around will tell you that these things exist and people do build them.
You can use Google to prove to yourself that either the infosec industry really exists (including skilled full time reverse engineers) or there is a vast conspiracy. Same as you would prove to yourself that nuclear submarines exist, without ever being allowed onboard one to inspect it.
Consider all the people who study closed source browsers (MSIE) and plugins (Flash) to write malware. Consider all the people who reverse engineer malware to write protections or ransomware decryptors.
The people who can do such work don't work exclusively for the NSA and Google, and you can probably hire them for $1000 a day. but none of them will do tricks for you for free just to prove that they exist. They're too busy making money.
I saw some of the work described in this [1] excellent paper on reverse engineering NSA's crypto backdoor in Juniper equipment being done live on twitter. People exchanging small pieces of code, piecing together all the changes that were made in order to allow passively decrypting VPN traffic.
Are you asking me to "back up" the claim that security researchers use BinDiff tools to reverse out vulnerabilities from vendor patches?
At one of the better-attended Black Hat USA talks last year, a team from Azimuth got up and stage and walked the audience through an IDA reverse of the iOS Secure Enclave firmware. Your argument is that it's somehow harder to reverse a simple iOS application?
