Well here's a possible scenario if ham radio came into being today. It is
based on the following hypothetical history.

1. Radio was developed by commercial interests and government.
2. Hams were allocated bands as the commercial interests and government
interests increased or decreased usage of bands.
3. Hams would be allowed technical experimentation. This is quite a
stretch as it would be hard to justify when there is no history of
contribution by hams.

Based on this here is what I would conjecture.

1. Amateurs would have no VHF or higher frequencies as these would be
completely allocated to commercial and government interests.
2. Limited HF access would be granted as the commercial & government users
migrated to satellite for worldwide communications.
3. Initial operations would be HF AM as sideband probably would not have
been developed by commercial interests and only experimented with in
government/military apps.
4. No FM would be allowed as hams would have no bands with sufficient
bandwidth available for FM use.
5. Eventually hams would turn the experimental government use into
practical application since they would need to find ways of narrowing the
signals to permit more users to occupy what would probably be much more
limited HF spectrum than we now enjoy.
6. Hams would try developing digital modes. Probably the first to be tried
would be packet as it uses a modulation scheme like that which connects
computers to the Internet. Since HF packet would prove to be too subject to
disruption by natural static, it's use would become minimal after the
initial flush of excited experimentation just as it has done in the real
history.
7. Hams would then search through other possible digital modes and
eventually light on RTTY, long abandoned by military users, but sufficiently
robust to stand up to the vagaries of HF propagation reasonably well. This
would a fairly steady level of popularity.
9. However hams would continue to experiment with modes. They would seek
simple, basic non-computer driven mode to use when voice was getting not
through and when computer was unable to decipher the digital signals. They
might light on the idea of using Morse code transmitted via a simple on/off
keying of the radio. As a simple, reliable, portable mode of operation, it
would be as popular as voice and far more popular than digital. There would
be frequent contests and everyone would be pestering the experts for tips on
how to get better at code.

The greatest difference between ham radio coming into being today versus the
actual history of ham radio is that amateurs would have no access to VHF and
higher frequencies. This I think would be quite a sad development.

Dee D. Flint, N8UZE