For me, i do not think everyone failed altcoins, instead altcoins failed us.
I do agree with you. How can be normal crypto users or investors are failed altcoin. If a project failed then total blame goes to the project team none others. Projects mainly fail because of not enough fund rising, have not good quality product to impress investors and not gain trust from investors or from the community. Now days projects just raise their fund and go away. So if some one to blame for failed it should be projects team.