2003 Lexus LX470

I STARTED THE CAR UP AFTER DINNER. ABOUT 2 MINUTES LATER FOUR WARNINGS LIGHTS RELATED TO THE BRAKING SYSTEM WENT OFF (ABS VTRAC BRAKE VSC) FOLLOWED BY A LONG WARNING BUZZ AND THEN A COMPLETE LOST OF BRAKING POWER FROM THE PEDAL AND THE HANDBRAKE. I WAS ABLE TO COME TO A COMPLETE STOP AND THEN TRIED TO RESTART THE VEHICLE TO REMEDY THE PROBLEM. IT DID NOT SOLVE THE PROBLEM AND SO FOR SAFETY REASON I CALLED FOR A TOW TO THE CLOSEST LEXUS DEALERSHIP. THE DEALER AT FIRST TOLD ME I HAVE TO REPLACE THE BRAKE MASTER CYLINDER WHICH COSTS ABOUT $3000 PLUS TAX. HOWEVER 30 MINUTES LATER THEY CALLED ME BACK AND TOLD ME NOW THE CAR IS WORKING FINE AFTER THEY'VE DRIVEN IT FOR ABOUT 5 MILES AND COULDN'T REPLICATE THE SYMPTOMS. SO I WENT TO THE DEALER AND PICKED UP THE VEHICLE. ABOUT THREE DAYS LATER, THE SAME THING HAPPENED AWAY WHILE I WAS GOING ABOUT 15MPH. AT FIRST THE FOUR LIGHTS WENT ON, AND THEN THE LONG BUZZ. THE CAR STILL HAD SOME BRAKE POWER WHICH I MANAGED TO DRIVE IT BACK INTO MY GARAGE WHEN THE BRAKE POWER THEN LOST COMPLETELY. I THINK WITH VEHICLE LIKE THIS, ESPECIALLY WEIGHING ABOUT 3 TONS, THERE SHOULD BE A BACKUP SYSTEM WHICH WILL ALLOW THE CAR TO HAVE SOME BRAKING POWER EVEN IF THE ELECTRONIC ONES WENT OUT. AND THE COSTS FOR REPLACEMENT AND "A SINGLE POINT OF FAILURE" FOR SUCH A HEAVY FAMILY VEHICLE MAKES ME WONDER ABOUT THE RELIABILITY AND SAFETY OF LEXUS CARS. I AM TRYING TO DECIDE WHETHER I SHOULD HAVE THE BRAKE MASTER CYLINDER REPLACED OR NOT, OR SHOULD I TRADE IN FOR A DIFFERENT VEHICLE. I UNDERSTAND THERE WAS A SIMILAR RECALL FOR IS, RX, AND ES. WOULD THIS BE RELATED ALSO? *TR