Cap idea

I was thinking about the NBA and team stability. In the NBA it seems there is a lot of player movement. Maybe too much player turnover? I think the cap system is largely responsible for this. The older pre-cap systems had players play entire careers in one uniform (will P.J be the last Bruin with this honor). As a fan some appreciate this loyalty and continuity. So my idea to encourage ream loyalty and give the home team an advantage in the UFA market, would be something along the following lines. After x (3?) years players can be given a bonus of some percentage of their cap contract (also %3?) per year of service to their team that is not counted against the cap. Here is an fictional example - at 10 years into his Bruin career at age 28 Patrice Bergeron is ready to sign a UFA contract. On the open market he is expecting to get 10 million per year(easy numbers, inflation and he is the leagues most dominant 2 way center ;) ). Any team in the league can offer him this amount as long as they can make it work with in their cap. The Bruins having had him for 7 years beyond the first 3 can offer him 21 percent or 2.1 million more cap free and would then have an advantage on the open market. Of course this bonus money would be forfeited in the event of a trade to keep the cap numbers easy. And for this reason I would expect no trade clauses to become more common etc.