I'm sorry but is that seriously why you think Take That sell like they do because people buy their stuff as gifts for relatives etc? I suppose thats why their tours sell out in hours all the grannies being bought tickets as Christmas presents.
They sell like they do simply because they are THE best around, simple as. They sell more in the UK than anyone else thats all the evidence needed. The Circus was a poor album but it still sold over 2 million copies to date. 2.6 million to date Beautiful World, 1.8 million in six weeks for Progress, 1.5 million tour tickets sold and such high demand that phone lines all over the place crashed.
They may not be your cup of tea thats absolutely fine but give them the credit they deserve you belittle yourself and delude yourself by not doing so.