From which angle it will be looked at, reaching a deal on Brexit already was and will be virtually impossible. All the necessary steps to be taken in the UK even to be able to create a minimally required sound fundament for exit (legally and politically) will take an infinite time in the UK parliament to complete, even if such succeeds. General elections, referenda, and extensions on Article 50 will never resolve such.
As a result, this inevitably mounts to a shear unbearable pressure within the UK and at the EU and this will bring serious damage to the already weakening relationship between the UK and the EU. Extending the period this will only make things worse. Sometimes, especially in dynamic times like these, it is better to take the firm decision and to start building up again from there.