Except that in practice regulation nearly typically protects big incumbents
from startup competitors. That is
exactly the effect GDPR had in Europe:
https://techcrunch.com/2018/10/09/gdpr-has-cut-ad-trackers-i...
Incumbents, especially in the tech industry, face a greater threat of being unseated by a startup than being unable to handle regulations. The "heavy hitters" have plenty of cash available to pay for the lawyers needed to deal with regulations, and the lobbyists needed to shape regulations to their advantage. Startups need to be careful about their budgets, and the added cost of compliance represents an entry cost that will almost certainly work against small players.
Moreover, when you regulate to the point where the big incumbents suffer economically, you are typically in a state of over-regulation. The evidence is very clear that numerous freight railroads failed in the 1960s because over-regulation prevented them from adapting to new realities; it was too difficult for the railroads to shut down unprofitable routes due to service requirements and they were required to continue paying taxes and maintenance costs on redundant infrastructure. Following deregulation (the Staggers Act) America's freight rail industry was able to reorganize and become profitable once again (and today the North American freight network is one of the most efficient systems on earth and is envied by the world). Passenger railroads are still uneconomical even in regions with high population densities that are absolutely dependent on passenger service (e.g. the northeast corridor, which is the ideal scenario and home to some of the only services that manage an operating surplus) largely because of persistent over-regulation (especially safety -- Acela trainsets are significantly heavier than comparable equipment in Europe and Asia and are more expensive to operate).
Good regulation is certainly possible, but it is the exception rather than the rule. The more typical pattern is either the economic failure of an industry (over-regulation) or regulatory capture.