Why this happens so often
Because the company is run by neighbours. A management company in a converted house or a small block is typically owned and directed by the flat owners themselves, who did not set out to be company directors and often do not know that they are.
Accounts go unfiled, confirmation statements lapse, and the registrar eventually strikes the company off. Nobody decided to let it happen.
What it costs when it does
Reinstating a struck-off company is possible and it is expensive, and it takes time that a transaction does not usually have.
In the meantime the practical consequences are immediate: there is no entity to insure the building, to collect contributions, to grant consents or to sign the paperwork a buyer's solicitor needs. The Lexsure wording below puts the effect on mortgageability and saleability plainly.
Where the management company fails, the lease will often make the landlord responsible instead — which is a real protection where there is a solvent landlord and no protection at all where there is not.
What to check, and what to do
Before buying: look the company up. Companies House is free and public, and the filing history tells you more about how a building is run than any amount of correspondence. Look for late filings, proposals to strike off, and whether there are any directors at all.
Ask who the directors are and whether they are the current flat owners. A company whose directors sold up and moved away years ago is a company nobody is steering.
After buying: take the role seriously. Where you are a member of the company, its compliance is your interest as much as anyone's, and the cheapest moment to fix a lapsed filing is before it becomes a strike-off.
The lease also gives you rights against the company and the landlord if obligations are not met. Those rights are worth exactly as much as the entity they are exercised against is worth, which is the honest and uncomfortable point the Lexsure wording makes.