I think major factors in people bitching about the Windows 10 EOL is that a) Windows 10 was explicitly marketed as the final version of Windows and b) Windows 11 is so unappealing that even companies are reluctant to upgrade.

Normally, that wouldn't be a big problem. We had dud releases before. Windows Vista had few friends due to compatibility issues but was workable. Besides, 7 was launched shortly after Vista's EOL. Likewise, Windows 8's absurd UI choices made it deeply unpopular but it was quickly followed by 8.1, which fixed that. And Windows 10 again followed shortly after 8's EOL (and well before 8.1's).

Windows 11, however, combines a hard to justify spec hike with a complete absence of appealing new features. The notable new features that are there are raising concerns about data safety. In certain industries (e.g. medical, legal, and finance), Recall/Copilot Vision is seen as dangerous as it might access protected information and is not under the same control that the company has over its document stores. That increases the vector for a data breach that could lead to severe legal and reputational penalties.

Microsoft failed to satisfyingly address these concerns. And there's not even hope of a new version of Windows releasing a few months after 10's EOL; Windows 12 hasn't even been announced yet.

It's no wonder that companies are now complaining about Windows 10's support window being too short.