It's also the chemistry of the players in a certain team, just like what you mentioned, it looks good in paper but in reality the players might have different mindset and they are not in the same page. But if players are hungry, like the Celtics, with Pierce, Allen, KG and Rondo it was a instant click and they become champions.
Another bad example is the KD, Irving and Harden in the Nets, too much drama and then they don't have enough supporting cast. I think this is one important aspects as well, players that are willing to do the hard job, and we've seen teams to have this special kinds of players as second stringers to play defense.
I think Lakers adding more players make sense, they need some people around the Luka Lebron duo, right now they have not that many great people around them and that should be the key point for them to get better. I get that it is not going to be easy, because they do not have any assets, and they do not have room in salary cap to get good free agents too.
Only possibility they have right now to get better would be someone willing to trade some great potential players with low salary to them in exchange of their bad players. But that's not going to happen, why would anyone be willingly help Lakers to get better on a trade. That already happened with Dallas giving them Luka, not really thinking they will get lucky like that again.