It's not that different, underperforming managers were sacked as regularly. Why do people think that it's a new thing?
Overall yes, I was speaking more about us in particular. United of 1991 was a cup team whose last league title win came 2 decades prior, in a league with similar level of spending across the board, with no culture and expectation of winning. United of 2021 is a juggernaut whose financial health relies heavily on successes on the pitch, in competition with mega money from states and oligarchs, and with a culture and expectation of winning built on 2 decades of domestic dominance. The situations, pressure, circumstances are vastly different to the point you can't just give a coach who have been in the business for more than 10 years with only a couple of Norwegian titles to his name the same latitude you once did a winner of the Scottish league, a respectable top level league back then, who also won the CWC against Madrid, but I'm sure you know all this.
The problem is you can never build long term success, especially in a league with many good clubs. You need to build up your team and backroom staff in order to deliver continuous success. This is what United have done in the past and I'm getting a bit annoyed at people who want us to just be some soulless entity. It's not a defence of Solksjaer, it's more of a culture that some United fans want us to develop of being like Chelsea.
It won't be long before we're sacking off kids too and we end our record of always having talent from the academy in our first team. Maybe we can also move out of Manchester so we attract more top talent as well.
Demanding excellence from the team isnt 'want us to just be some soulless entity'. Would you call Bayern Munich soulless? Barcelona soulless? Juventus soulless? Real Madrid soulless? Do you expect any of them to tolerate 'one of their own' the way we did Solskjaer these past 3 years?
Continuous success doesnt magically appear by tolerating mediocrity sentimentally for a few years. Continuous success is built by actually succeeding and never letting up, constantly striving to better yourself in all aspects of the club, from the facilities to the support staff to the youth set up to the first team. The plain and simple truth is way too many supporters of this club have gotten used to excusing its failings in the name of tradition.