Yeah, maybe this can be a great end to your campaign, but when i say end i
mean end, you can't go anymore, instead you have to save another time the
world and it can become too, too, unrealistic to even play blindly.

I dunno the great solution to this problem, but if we agree that let our Pcs
go high in level in a super rate, a lot more than other abitants of Cerilia,
and if we agree that is unrealistic that all people involved with us gain
levels like our pc, following their rate, and if we agree that all this
unrealistic stuff will lessen our enjoy level, we must find a way out. Maybe
we can use all the BR unique stuff and make great, great adventure without
go higher than, for example, 7th lv, not saying that our pcs stop there, but
that they need years to gain even one level.
It seems to me that Rich Baker himself is saying to do this to us when he
create a spell system unique to BR (realm spells) that is semi-unreleted
with character level but depends more to his role-play situation.
I searched just now only on the BR rulebook and i saw that the most
requiring spells need that your only 7th, that is, not all our wizard
regents must have the power to cast the greater spells, like not all wizard
must have the power to cast wish, instead it become less enjoyable. So, it
seems, Rich is saying us that our wizard regents must be beetwen 4th and
6th, to say, and only rarely more than 7th. It depend on your DM, after
that, and on his creative mind, to let you enjoy without need of levels.

IMHU in setting like FR it can be truly impossible to live without going up
in level, cause if read the books you find a lot, and more, of character
higher than 15.
But in BR first the people are of lesser levels and second there are a lot
of way in enjoying without all that.

Nadastor, Wizard of the Black Robes
"The power of a man is not in his hands, but in his eyes !
His life is not into his body, but into his mind !
The world is not around him, but is in him !"