Dr. Rox,
The current baseline shown earlier in the Timeline above is a 3:41  for the 1042 to 1423 Locarno/Domodossola/Spiez/Interlaken West run.
 If you access 
http://www.myswissalps.com/swisstimetable.asp?lang=EN you will get the information I indicate below. When you put in Locarno to Luzern starting at 1030, the choices you get are:
Details Station/Stop  Date Time Duration Chg. Travel with 
1  Locarno 08.02.09  dep 10:45    3:09  1  IR, S3   
 Luzern    arr 13:54  
  Locarno 08.02.09  dep 10:45 1  
IR 2280  InterRegio,    
 Arth-Goldau  arr 13:06 4  
  Arth-Goldau  dep 13:21 6  
S3 21350  Urban railway, line 3  
 Luzern  arr 13:54 5  
Duration: 3:09; runs daily   
2  Locarno 08.02.09  dep 11:03    2:38  1  S20, ICN   
 Luzern    arr 13:41  
Details - Connection 2       
Station/Stop  Date Time Platform Travel with Comments 
  Locarno 08.02.09  dep 11:03 3  
S2014238  Urban railway, line 20  
 Bellinzona  arr 11:27 1  
  Bellinzona  dep 11:36 1  
ICN 666  InterCity tilting t,   BZ RZ  
 Luzern  arr 13:41 7  
Duration: 2:38; runs daily   
3  Locarno 08.02.09  dep 11:45    2:56  0  IR   
 Luzern    arr 14:41  
Details - Connection 3       
Station/Stop  Date Time Platform Travel with Comments   
4  Locarno 08.02.09  dep 12:03    2:38  2  S20, CIS, IR 
Details - Connection 4       
Station/Stop  Date Time Platform Travel with Comments 
  Locarno 08.02.09  dep 12:03 3  
S2014242  Urban railway, line 20  
 Bellinzona  arr 12:27 1  
  Bellinzona  dep 12:36 1  
CIS10016  Cisalpino,     
 Arth-Goldau  arr 14:09 4  
  Arth-Goldau  dep 14:14 5  
IR 2178  InterRegio,   
 Luzern  arr 14:41 7  
Duration: 2:38; runs 8. Feb until 13. Jun 2009 daily  
Then we must connect in Luzern:
Details Station/Stop  Date Time Duration Chg. Travel with 
1  Luzern 08.02.09  dep 13:55    2:09  1  IR, IC   
 Interlaken West    arr 16:04   
2  Luzern 08.02.09  dep 13:55    2:21  1  IR, BUS   
 Interlaken West, Bahnhof    arr 16:13   
3  Luzern 08.02.09  dep 13:57    2:26  2  RE, IC, R   
 Interlaken West    arr 16:23   
4 Luzern 08.02.09  dep 14:55 12  
IR 2228  InterRegio,     
 Interlaken Ost  arr 16:55 4  
  Interlaken Ost  dep 17:01 5  
IC 986  InterCity,    BZ RZ  
 Interlaken West  arr 17:04 1  
Duration: 2:09; runs daily   
When you combine the two, you get :
Lorano 1045 Luzern 1354 5 hours 9 minutes
Locarono 1103 Luzern 1354 4 hours 51 minutes
Locarno 1145 Luzern 1704 7 hours 19 minutes
Locarno  1203 Luzern 1704 7 hours 1 minute
I believe that you are using non-Sunday timetables, which is not permissible when the date in question is Sunday Nov. 2. If you use Sundays, you will duplicate my results. The only possible conclusion is that the St. Gotthard route via connection in Luzern is NOT competitive by 1 hour 24 minutes longer or more.
EDITOR's NOTE - I discovered I had made an assumption about all such trains going through Bellinzona, but that it not correct. So I redid the entire analysis.