That's what browsers actually did.

Browsers started ignoring the 2 connection limit on H/1.x long before H2 came along

Came here to say the same thing; had they read the RFC they'd realize it's not actually a limit, just a suggestion - thats why its in the "Practical Considerations" section too.

Whomever downvoted you is probably unaware words like SHOULD have specific meaning in RFCs