I think if you are a regular airline traveller, used to making your own bookings on business trips through the year, confident about getting taxis in an overseas airport or finding your rental car, etc, then you can often find you can string it all together yourself better and cheaper. And if it turns out more expensive, you can always fall back on the tour operator.
There are a lot of IT pax who just wouldn't know where to start with all this, and they are the staple market for tour operators. Unlikely to be PPRuNe readers of course ! However as time goes on more and more of us fall into category 1.
Tour operators need to find a way for such travellers to find real "added value" in what they do. This does not include for example having "on-site representatives" who are not paid to do this side of the job, only living on commissions on day excursions they sell. Nor does it include taking hours to do the transfers with a 50-seat coach picking up 5 people in one town, 3 people in another etc (all of whom were given the same time to be ready !). Expectations have moved on.