I agree with you OP in many ways: it feels like we should be allowed to do more by now, the "sadly death" figures are low, and to ditch those symbolic masks facial badges of "I believe in the virus" . I want to be playing netball, and the PROPER game, not the modified "no shouting allowed, stand four feet apart" version which we MIGHT be allowed to play in September: how dare Boris take away our exercise, and then tell us we're too fat. Our glorious leader told us "we can turn this virus around in twelve weeks", "it's just to flatten the curve", his nose being so long he can't put a mask on.
I think the government doesn't want to go down the route of draconian enforcement (much as many on Mumsnet would love this), or maybe they can't because they've cut police numbers so much, so instead, they're keeping restrictions for as long as they can, while people are still playing nicely (why are we not rioting by now?!), and believing in the virus. Also, the public mood is still that many people are too scared to go back to normal, so either the government is milking that while they can, or they don't want to be seen to be "rushing" people back. They are clearly playing their cards to be able to blame the public as much as they can if things go wrong, while saying "we told you so".
We do have the tricky matter of the schools reopening, which absolutely MUST happen. I'm a huge lockdown sceptic, and I'm almost scared that the public is blindly complying while asking no questions, but to use a hideous phrase of back-from-the-dead-Saint-Boris, "it could go either way": we could see infections go up again, or they might stay low (please, please, please, please!). I suspect also that Bojo wants to be able to ban Trick or Treating if he feels the need, and to have the option of keeping people apart at Christmas. Maybe cancelling Eid was a symbolic "look at what I might do to Christmas if you don't behave".
@StealthPolarBear You're right that the government are keeping their lips sealed behind their masks about reviewing anything: the silence on this is deathly. Didn't they make reviews less frequent, while our backs were turned? And scrapping the daily briefings, when they didn't have so much bloodshed to tell us about. We need to keep up pressure on the government that we are not going to put up with this "new abnormal" for ever; if we're too docile and compliant (and I think it's scary how little the public are questioning the restrictions), they will indeed keep the restrictions in place for longer. Nothing was said by the government about the mandated masks being temporary - they assumed that we're used to them pulling restrictions out of their magic hat on a whim, and that we're not going to question it, that we're brainwashed by the phrase "new normal". We need to be questioning the hell out them!!!! I wrote to my MP seeking clarification on masks being temporary: amidst the usual politician's waffle, there was the sentence "I assure you that the restrictions will be temporary".