there are A LOT of zip files using lzma in the wild.
also, how about people learn to use updated software? should newer video compression technologies not be allowed in mkv/mp4.
if you cant open it, well.. then stop using 90ies winzip
No. You can't get people to use updated software. You can't get a number of people to update past windows 7. This has been and will likely remain a persistent issue, and it's sure not one you're going to fix. All it will do is limit your ability to work with people. This isn't a hill on which you should die.
im okay with that. That being said, I have not had a single issue delivering zip files with lzma, and i KNOW that I have gotten MANY from the random sources.
I would also expect people to be able to decode h265 in an mp4 file.
Your proposal seems, to word it bluntly, retarded. You would have mp4 frozen for h264 for ETERNITY, and then invent a new format as replacement? or you would just say "god has bestowed upon the world h264, and it shall be the LAST CODEC EVER!".
get with the program. Things change, you cannot expect to be forwards compatible for ever. Sometimes people have to switch to newer versions of software.
If your customer is stuck in the 90s because his 90s technology works perfectly fine and he has no intention to fix things that are not broken. Then deliver stuff that is compatible with 90s technology. He will be happy, will continue to work with you and you will make money.
If your customer is using the latest technologies and values size efficiency, then use the latest codecs.
I usually default to being conservative, because those who are up to date usually don't have a problem with bigger files, but those who are not are going to have a problem with recent formats. Maybe overly so, but that's my experience with working with big companies with decades long lifecycles.
Your job is not to lecture your customer, unless he asked for it. And if he asked for it, he probably expects better arguments that "update your software, idiot". Your job is to deliver what works for him. Now, of course, it is your right to be picky and leave money on the table, I will be happy to go after you and take it.
Installing new software has a real time and hassle cost, and how much time are you actually saving over the long run? It depends on your usage patterns.
In the middle of San Francisco, with Silicon Valley level incomes, very possible. In the real world I still exchange files with users on rustic ADSL, where every megabyte counts. Many areas out there, in rural Mongolia or in the middle of Africa that's just got access to the internet, are even worse in that regard.
if you cant open it, well.. then stop using 90ies winzip