Yes, I am that annoyed, because I don't want to play against other people. It takes more time and is way too stressful for me. SP in GT6 would be "fixed" for me if they allowed standing starts in the campaign. GTS having so little SP content is a huge bummer for me, because I like the series. Bought GT5 and GT6 day one and even though I've been burned by those purchases, I'd still be there for GTS, if it had a similar amount of SP content and at least a good 100 road cars.
I don't want them to ditch the focus for GT Sport, but I'd appreciate it if they'd throw users like me a bone and not leave me without an alternative. I've read that they're going to patch more SP content in later, but I'm definitely going to wait for a while. Same goes for the price for the DLC cars.
There's still the single player challenges, arcade mode and new single player races that will be added.
You should give online a shot though - it's not as bad as you think and with the rating system you'd hope that you'd be placed in races with even opponents