They can do something but what will be the feedback of the community if they will do that?
Remember the Kiefer Ravena issue wherein PBA, even in the right stand, still got backlash from the community and I think even here in this thread because people think they are getting the way of Kiefer to play abroad? If the community will not support them about it then it will affect PBA's reputation so better not take action and just allow their players to play abroad. In the case of Dwight Ramos, it's just fine to play abroad since after all, he's not in PBA yet.
It's also easy for others to say that PBA players should have a high salary but it's not that simple to approved. That's why there are good perks offered instead in case of a good run per conference wherein in some cases, the perks are much higher compared to the salary of the player that usually receives.
Because when they give big salary, big portion of that will still go to the government due to taxes, so they will give some allowance or reward instead as they could play it not to pay taxes on it, or if they will, it would only be a minimal amount. Unfortunately, this is only good for good teams as they are the teams that will likely be in the Finals or in the playoffs, low ranking teams will not have this kind of benefits.
Actually, it's not about the tax as the main concern.
There's a salary cap for each team. The purpose of it is to balance everything so that dominant teams can't just acquire and offer a big contract to a superstar. In the case of the NBA, it's effective because the majority of teams there can afford to spend a luxury contract if necessary. In the case of PBA, not that effective because only a few can handle the big cost. If PBA boards will allow another increase in salary cap per team, it will just result for SMC teams as an example to become more dominant because they afford to spend big unlike smaller teams.
That was critical and a sensitive issue because not all companies in the PBA are having the same level. That's one of the reasons why salaries in PBA can't just simply increase. Perks are also limited in terms of legal terms but as we know SMC is giving their players more of it under the table if a certain achievement was made.