It occurred to me that since wizards in 5e are allowed, upon encountering another wizard's spellbook, to copy spells of a level that they can cast into their own spellbook (at the cost of only time and gp), a party with multiple wizards could simply collude and spread large quantities of spells amongst themselves. E.g. "Ok, Jones over there will be the one to learn Fireball as his next target of research, and then he'll let us copy it from him. Jones, what spells do you want in exchange from us?"
Is there any reason for discouraging this, especially from a roleplaying perspective? Would most wizards consider this a very un-professional thing to do? Are there strong societal pressures to avoid sharing one's hard-earned spells even with one's closest friends or allies? E.g. "I'm willing to entrust my life to this other wizard in my party, let him carry my gold, trust that he's not going to stab me in my sleep the next time I take a Long Rest, but I'm not willing to let him copy even a single level 1 spell from my spellbook. That's M I N E!".