i can only really speak for the UK, the reason why we have a distinct lack of tumbling is because it was never part of our score sheets for a long time. it scored you extra if you had it, but you were lucky if you seen 1/2 backhandsprings TOTAL at a competition. A good few years ago it became a compulsory part of our score sheets, since then we have built and built on what we have but we do not have the experience and facilities, gyms are pretty rare here, gymnastics facilities are a little easier to come by but you will pay just as much to attend there as you would for your cheer.
the coaches ive worked with have gained the experience now but we have many senior teams (age 14+) that are starting from cartwheels, in church halls etc they arent progressing to fulls etc at a fast pace but the younger teams coming out are mostly level appropriate and as they get older their skills are progressing, give it 5/6 years and i HOPE our senior teams will be team tumbling at level 5
things are definitely on the up for international tumbling, it is not through lack of trying for most athletes ... there are still programmes that haven't moved with the times and realised we need to work the WHOLE scoresheet