I'm not wild about blowing my entertainment budget for the month in one meal, which is what would happen if I paid for 4 people, though on a long enough time horizon (decades?) it might work out the same in the end.
Also much easier when you're rich than when you're not.
I don't want to have to worry about my friend's finances when inviting them out (I want to grab sushi with Irene, but can she can afford it?).
They can pick a cheaper place or invite me over for a home-cooked meal if they can't afford to invite me out to a nice restaurant.
I work in tech while most of my close friends are still students, the point is to be able to do nice (more expensive) things with them, which we could never do if we always split the bill.
Try that with a group of 8-12 people, especially if they all want to be charged different amounts. Some places will do it, but many wont. A lot easier for one person to pay, and others to pay them back with cash (or one of the million free payment apps like Venmo).
If you're splitting the check, you have to tell the waiter who to charge for what. If you're lucky, everyone ordered their own meals and drinks and nothing was split. Then you can usually just say "this card is mine, this card is hers, this card is his" and it works. Otherwise, you usually have to break out a pen and tally up everyone's share and write it on the back of the bill or somewhere like that.
Then the waiter goes away with your cards to the register (or a computerized POS system), runs the charges, and hopefully doesn't copy your card for their own fraudulent use. They get separate printed receipts for each paying diner and bring them back to the table along with the cards and any change (if people paid in cash).
People paying in card add their tips to the receipt and sign it, and people paying in cash leave their tips on the table. Then you're done.
Suffice it to say that this is a huge pain in the ass for everyone involved, and takes time that the waitstaff could be using to provide better service to other customers. Also, especially for smaller restaurants running on an extremely narrow margin, the credit card fees for splitting a table too many ways can be financially unacceptable.
But I still like splitting check much more. It allows me to spend/not spend how I want regardless of whether I am least or most willing one to pay for more expensive things. If I drink/eat a lot I pay a lot and I don't have to feel bad about somebody else paying it. And if I want to save money, I don't drink and don't have to worry about friend eating a lot.
"can we split for this pizza delivery?"
"can we do an iou for my friend who forgot their card?"
"can we split this utility bill?"
I think it's simple common courtesy that the person extending the invite picks up the check.
Outside of my family, I've also had friends from relatively poor backgrounds insist on paying for lunch or drinks before. And I've had wealthy friends act extremely petty down to the penny. So overall I've found it's hard or impossible to generalize too much.