@Ray777 - raising trees from seeds takes time. It is quite likely you are assuming most bonsai are grown from seeds. And my fellow forum mates are happily jabbering along down the path leading you to believe they all create ALL their bonsai from seed.
Truth is, yes, at some point in time all trees come from seed. Second truth, only a small percentage of bonsai trees exhibited were started by seed by the exhibitor. Most of us get our bonsai "by other means", we do not start all our bonsai from seed because it simply takes just too damn long for the majority of species. There are exceptions. If you live in a mild climate with short winters, you can raise Japanese black pines, trident maples, japanese maples, and some elms in a time span acceptable to mere mortals. But the majority of bonsai folk do not start with seedlings for the majority of their bonsai trees simply because it takes too long.
Raising trees from seeds for bonsai is the "nurseryman's phase" of the bonsai hobby, and most of us leave it to professional nurseries.
Best way to get a tree that looks like it is 100 years old is to start with a tree that is already 200 years old. The quickest route to mature looking bonsai is to start with trees collected from the wild. Naturally dwarfed and stunted trees growing on cliff faces in the mountains make classic bonsai. Wild trees collected from the mountains are called '"Yamadori", where "Yama" means mountain. Trees can also be collected from stream banks, river cuts, forests, anywhere. Key the tree needs to be naturally dwarfed or twisted and broken to create interesting shapes. If the first 6to 12 inches of trunk are interesting, the tree is worth collecting. If the first 6 inches of the trunk are straight and boring, the tree should be given a pass. If a tree is collected from someplace other than the mountains, it is not call "yamadori", it is just a "collected tree".
Trees can also be collected from orchards and hedgerows, windbreaks and roadsides.
Trees can also be collected from nurseries.
Often the trees we start working on are 5 to 15 times taller than the finished bonsai we want to create. If I am looking to make a 24 inch tall ginkgo or hornbeam, I will want a 4 to 6 inch diameter trunk. In order to get a 4 to 6 inch diameter trunk I need to be looking at trees in the nursery that are 10 feet to 20 feet tall or even a little taller. When I find a trunk the right diameter, with a little wiggle in the first 6 inches to make it interesting, that is the tree you pick up. It saves many, many years over starting from seed. We then cut these 10 or more foot tall trees down to 24 inches, or even smaller in some cases.
Most bonsai are cut down to size rather than "grown up to size" from seed or cuttings. Most bonsai spend at least 5 years or more many times larger than their final size.
It is rare that bonsai are ONLY "grown up from seed". Vast majority of time, bonsai are grown large, then brought down to size.
Most of our forum member are conscious of this, and do this, but just have been neglecting to mention this.